R = laps she runs
s = laps she swims
each r (laps she runs) takes 5 min.
each s (laps she swims) takes 3 min.
She wants to run for 30 min.
So your inequality should = 30
The answer is the third one
Area of trapezium= 1/2 × (a+b) × h
= 1/2 × (12 + 8) × 8
= 1/2 × 20 × 8
= 10 × 8
= 80 cm^3
Hope it helps you
I think it is 22.5, since molly has 75% of the packs