Dana and Vanessa collected stamps. Dana gave 30% of her stamps to Vanessa and as a result, Vanessa's stamps increased by 10%. If Dana had 84 stamps left, find the number of stamps Vanessa should give to Dana in the end so that both had an equal number of stamps.

	Dana	Vanessa	Comparing the change in Vanessa'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 Vanessa had is repeated.  Make the increase in the number of stamps that Vanessa had the same. LCM of 3 and 1 = 3

7 u = 84

1 u = 84 ÷ 7 = 12

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

Number of stamps that Vanessa should give to Dana so that both had an equal number of stamps in the end
= 26 u ÷ 2
= 13 u
= 13 x 12
= 156

Answer(s): 156