There was an equal number of chikoos and starfruits. On Monday, some chikoos were added, such that the number of chikoos increased by 60%. On Tuesday, the number of chikoos further increased by 50% and the number of starfruits decreased by 10%. There were 90 more chikoos than starfruits in the end. How many chikoos and starfruits were there altogether at first?

	Chikoos	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 chikoos added on Monday
= 60% x 1 u
= ⁶⁰₁₀₀ x 1 u
= 0.6 u

Number of chikoos increased on Tuesday
= 50% x 1.6 u
= ⁵⁰₁₀₀ x 1.6 u
= 0.8 u

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

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

1.5 u = 90

1 u = 90 ÷ 1.5 = 60

Total number of chikoos and starfruits at first
= 1 u + 1 u
= 2 u
= 2 x 60
= 120

Answer(s): 120