Solve the following system of equations by elimination method
6(ax + by) = 3a + 2b
6(bx - ay) =3b - 2a.
Let the number of 20 paise coins = x
and number of 25 paise coins = y
Then, value of 20 paise coins = 20x
and value of 25 paise coins = 25y
Case I. x + y = 50
Case II. 20x + 25y = 1125
[∵ 11.25 = 1125 Paise]
Thus, we have
x + y = 50 ...(i)
20x + 25y = 1125 ...(ii)
For making the coefficient of ‘x’ in (i) and (ii) equal, we multiply the (i) by 20 and then subtracting, we get
Putting the value of ‘y’ in (i), we get
x + y = 50
⇒ x + 25 = 50
⇒ x = 25
Hence, the number of 20 paise coins = 25 and the number of 25 paise coins = 25.
A motor boat whose speed is 24 km/h in still water takes 1 hour more to go 32km upstream than to return downstream to the same spot. Find the speed of the stream.
If the points A(k + 1, 2k), B(3k, 2k + 3) and C(5k – 1, 5k) are collinear, then find the value of k.