PSLE
At first, Sam had some money. He spent ¹₄ of it on a jumpsuit and ²₇ of the remainder on a dress. After that, his uncle gave him $220. The ratio of the total amount of money he had in the end to the amount of money he had at first was 5 : 4. How much money did Sam have at first?
Fraction of the total on remainder
= 1 - ¹₄
= ³₄

Fraction of the remainder on what was left 
= 1 - ²₇
= ⁵₇

Fraction of the total on what was left
= ³₄ x ⁵₇
= ¹⁵₂₈

The total at first is the repeated identity.  Make the total at first the same. LCM of 4 and 28 = 28

Total in the end : Total at first
5_x7 : 4_x7
35 : 28

Amount that his uncle gave him
= 35 u - 15 u
= 20 u

20 u = 220

1 u = 220 ÷ 20 = 11

Amount that Sam had at first
= 28 u
= 28 x 11
= $308

Answer(s): $308