Gabby and Diana collected stamps. Gabby gave 30% of her stamps to Diana and as a result, Diana's stamps increased by 10%. If Gabby had 63 stamps left, find the number of stamps Diana should give to Gabby in the end so that both had an equal number of stamps.

	Gabby	Diana	Comparing the change in Diana's stamps
Before	10x1 = 10 u		10x3 = 30u
Change	- 3x1 = - 3 u	+ 3x1 = + 3 u	+ 1x3 = + 3 u
After	7x1 = 7 u		11x3 = 33 u

30% = ³⁰₁₀₀ = ³₁₀
10% = ¹⁰₁₀₀ = ¹₁₀

The increase in the number of stamps that Diana had is repeated.  Make the increase in the number of stamps that Diana had the same. LCM of 3 and 1 = 3

7 u = 63

1 u = 63 ÷ 7 = 9

Number of stamps that Diana had more than Gabby in the end
= 33 u - 7 u
= 26 u

Number of stamps that Diana should give to Gabby so that both had an equal number of stamps in the end
= 26 u ÷ 2
= 13 u
= 13 x 9
= 117

Answer(s): 117