Question

A shopkeeper had some watches for sale. He sold a total of 342 watches

in January and February. In March he sold 25% of the remainder and was
left with 18% of the watches he had at first. How many watches did he
have at first?​

Answer 1

Answer: 450 watches

Explanation:

Given the following :

Let Initial number of watches = n

Total number sold in January and February = 342

Total sold in march = 25% of (n - 342) = 0.25(n - 342) = 0.25n - 85.5

Total watches left = 18% of n = 0.18n

Therefore,

Initial number of watches = (watches left + total watches sold)

n = 0.18n + (0.25n - 85.5) + 342

n = 0.18n + 0.25n - 85.5 + 342

n = 0.43n + 256.5

n - 0.43n = 256.5

0.57n = 256.5

n = 256.5 / 0.57

n = 450

n = Initial number of watches = 450