Answer:
Correct answer: t₂ = 70 minutes
Step-by-step explanation:
Given:
t₁ = 28 minutes and t₁₂ = 20 minutes, t₂ = ?
The necessary equation for this situation is:
1/t₁ + 1/t₂ = 1/t₁₂ => 1/28 + 1/t₂ = 1/20 => (28 + t₂)/ 28 t₂ = 1/20 =>
28 t₂ = (28 + t₂) · 20 = 20 t₂ + 560 => 28 t₂ - 20 t₂ = 560 =>
8 t₂ = 560 => t₂ = 560/8 = 70 minutes
t₂ = 70 minutes
God is with you!!!
