Eva and Barbara collected beads. Eva gave 25% of her beads to Barbara and as a result, Barbara's beads increased by 30%. If Eva had 90 beads left, find the number of beads Barbara should give to Eva in the end so that both had an equal number of beads.

	Eva	Barbara	Comparing the change in Barbara's beads
Before	4x3 = 12 u		10x1 = 10u
Change	- 1x3 = - 3 u	+ 1x3 = + 3 u	+ 3x1 = + 3 u
After	3x3 = 9 u		13x1 = 13 u

25% = ²⁵₁₀₀ = ¹₄
30% = ³⁰₁₀₀ = ³₁₀

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

9 u = 90

1 u = 90 ÷ 9 = 10

Number of beads that Barbara had more than Eva in the end
= 13 u - 9 u
= 4 u

Number of beads that Barbara should give to Eva so that both had an equal number of beads in the end
= 4 u ÷ 2
= 2 u
= 2 x 10
= 20

Answer(s): 20