There was an equal number of peaches and starfruits. On Tuesday, some peaches were added, such that the number of peaches increased by 60%. On Wednesday, the number of peaches further increased by 50% and the number of starfruits decreased by 10%. There were 15 more peaches than starfruits in the end. How many peaches and starfruits were there altogether at first?

	Peaches	Starfruits
Before	1 u	1 u
Change 1	+ 0.6 u	No change
After 1	1.6 u	1 u
Change 2	+ 0.8 u	- 0.1 u
After 2	2.4 u	0.9 u

Number of peaches added on Tuesday
= 60% x 1 u
= ⁶⁰₁₀₀ x 1 u
= 0.6 u

Number of peaches increased on Wednesday
= 50% x 1.6 u
= ⁵⁰₁₀₀ x 1.6 u
= 0.8 u

Number of starfruits decreased on Wednesday
= 10% x 1 u
= ¹⁰₁₀₀ x 1 u
= 0.1 u

Number of more peaches than starfruits in the end
= 2.4 u - 0.9 u
= 1.5 u

1.5 u = 15

1 u = 15 ÷ 1.5 = 10

Total number of peaches and starfruits at first
= 1 u + 1 u
= 2 u
= 2 x 10
= 20

Answer(s): 20