A certain is to be shared among three brothers ,one of them gets 2/5 of it,another gets 1/4 of it and the third one gets #2.10k. How much is the sum of money?

Answer 1

(2/5)x + (1/4)x + 2.10 = x

(8/20)x + (5/20)x + 2.10 = x

(13/20)x + 2.10 = x

2.10 = 7/20x

2.10 / (7/20) = x

2.10 * (20/7) = x

42/7 = 6 = x

It looks like the original was 6K.

Answer 2

(2/5)s + (1/4)s = (8/20 +5/20)s
= (13/20)s
so
(7/20)s = 2.10