Got no idea how to solve it:))

hi

total time group 1:

x/20=54 so x = 20 * 54 = 1080

total time group 2:

x/P = T so x = PT

new mean:

(1080+PT)/(20+P) = 56

1080+PT = 1120 + 56P

PT - 56P = 40

P(T - 56) = 40

P = 40/(T-56) option C)

1 Like