An open topped box is to be constructed by removing equal square

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsLong Answer Type

311. A wire of length 30 cm is to be cut into two pieces. One of the pieces is to be made into a square and the other into a circle. What could be the length of the two pieces, so that the combined area of the square and the circle is minimum?
78 Views

312.

The sum of the perimeters of a circle and square is k where k is some constant. Prove that the sum of their areas is least when the side of square is double the radius of the circle. 

106 Views

 Multiple Choice QuestionsShort Answer Type

313. A square piece of 30 cm is to be made into a box without top by cutting a square from each corner and folding up the flaps to form a box. What should be the side of the square to be cut off so that volume of the box is maximum?
79 Views

314. A square piece of a tin of side 18 cm is to be made into a box without top, by cutting a square from each corner and folding up the flaps to form a box. What should be the side of the square to be cut off, so that the volume of the box is the maximum possible?
87 Views

Advertisement
315. A square piece of tin of side 24 cm. is to be made into a box without top by cutting a square from each corner arid folding up the flaps to form a box. What should be the side of the square to be cut off so that the volume of the box is maximum ? Also, find this maximum volume.
119 Views

316.

An open box with a square base is to be made out of a given quantity of sheet of area c2. Show that the maximum volume of the box is fraction numerator straight c cubed over denominator 6 square root of 3 end fraction.

87 Views

 Multiple Choice QuestionsLong Answer Type

Advertisement

317.

An open topped box is to be constructed by removing equal squares from each corner of a 3 metre by 8 metre rectangular sheet of aluminum and folding up the sides. Find the volume of the largest such box.

 


Let x metre be the length of a side of the removed squares. Then the height of the box is x, length is (8 – 2x) and breadth is (3 – 2 x).
Let V be the volume of the box.
   therefore space space space space space straight V space space equals straight x space left parenthesis 3 minus 2 straight x right parenthesis thin space left parenthesis 8 minus 2 straight x right parenthesis space equals space 4 straight x cubed minus 22 straight x squared plus 24 straight x
space space space space dV over dx space equals space
and space fraction numerator straight d squared straight V over denominator dx squared end fraction space equals space
For V to be maximum or minimum.
                         dV over dx space equals space 0 space space space space space space space space space space space rightwards double arrow space 12 straight x squared minus 44 straight x plus 24 space equals space 0
rightwards double arrow space space space 3 straight x squared minus 11 straight x plus 6 space equals space 0 space space space space space space space space rightwards double arrow space space space straight x space equals space fraction numerator 11 plus-or-minus square root of 121 minus 72 end root over denominator 6 end fraction
rightwards double arrow space space space space space space straight x space equals space fraction numerator 11 plus-or-minus square root of 49 over denominator 6 end fraction space equals space fraction numerator 11 plus-or-minus 7 over denominator 6 end fraction space equals 3 comma space 2 over 3
Rejecting x = 3 as breadth cannot be negative, we get, straight x space equals 2 over 3
At space space straight x space equals space 2 over 3 comma space dV over dx squared space equals space 24 space open parentheses 2 over 3 close parentheses minus 44 minus 16 minus 4 space equals space 28 less than 0
therefore space space space space space space straight V space space is space maximum space when space straight x space equals space 2 over 3
therefore space space space space space space space volume space of space largest space box space space equals open parentheses 2 over 3 close parentheses space open parentheses 3 minus 4 over 3 close parentheses space open parentheses 8 minus 4 over 3 close parentheses space equals space 2 over 3 cross times 5 over 3 cross times 20 over 3 space equals space 200 over 27 straight m cubed.
127 Views

Advertisement

 Multiple Choice QuestionsShort Answer Type

318.

A rectangular sheet of tin 45 cm by 24 cm is to be made into a box without top, by cutting off squares from each corner and folding up the flaps. What should be side of the square to be cut off so that the volume of he box is maximum?

94 Views

Advertisement

 Multiple Choice QuestionsLong Answer Type

319. An open box with a square base is to be made out of a given iron sheet of area 27 square m. Show that the maximum volume of the box is 13.5 cubic m.
178 Views

320.

A square tank of capacity 250 cubic metres has to be dug out. The cost of the land is Rs.50 per square metre. The cost of digging increases with the depth and for the whole tank is Rs 400 h2, where h metres is the depth of the tank. What should be the dimensions of the tank so that the cost be minimum?

441 Views

Advertisement