Question

The SuperSave supermarket sells Birma washing powder for Rs 1.20 a bottle. At this price they are charging 50% more than the price at which they buy the item from the manufacturers. Next week SuperSave is having a ‘Buy two get a third free’ offer on this item. The supermarket does not want to lose money on this offer, so it expects the manufacturers to reduce their prices so SuperSave will make the same actual profit on every three bottles sold. By how much will the manufacturers have to reduce their prices? (a) 1/6 (b) 1/4 (c) 1/3 (d) 1/2 (e) 2/3

Answer 1

s = ut + ½at^2 …. (1)

v^2 = u^2 + 2as …. (2)

v = u + at …. (3)

s = (u + v)t/2 …. (4)

where s is distance, u is initial velocity, v is final velocity, a is acceleration and t is time.

In this case, we know u = 15m/s, v = 0, t = 5s and we want to find a, so we use equation (3)

v = u + at

0 = 15 + 5a

a = -15/5 = -3

The acceleration is -3m/s^2, and the negative sign indicates that it is a retardation.