2000 * .1 = 200 + 2000 = 2200 (First year)
2200 *.1 = 220 + 2200 = 2420 (second year )
2420* .1 = 242 + 2420 = 2662 (third year )
2662 * .1 = 266.2 + 2662 = 2928.2 (fourth year)
They spent $2928.2 on clothing for 4 years.
Then there would be 9 girls and 23 boys
sin(α) = ⁻⁵/₁₃
sin⁻¹[sin(α)] = sin⁻¹(⁻⁵/₁₃)
α ≈ 1.1256π
cos(β) = ²/₅
cos⁻¹[cos(β)] = cos⁻¹(²/₅)
β ≈ 1.6311π
sin(α - β) = sin(1.1256π - 1.6311π)
sin(α - β) = sin(-0.5055π)
sin(α - β) = -sin(0.5055π)
sin(α - β) = -sin(90.99)
sin(α - β) ≈ -0.116
