A = P(1 + r)^t is the interest formula
A = 1000(1 + .02)^t
A = 1000(1.02)^t
I'm not sure which of your two answers A or C have the t raised to a power but you need to choose the one with the t raised to a power.
They only have 1 common point
To find the answer,we need to first find out their hours spent individually.
Rishi spent:
=2×3/4
=6/4hours
Kyle spent
=6×1/4
=6/4hours
As they both spent 6/4 hours,they spent equal time.
Hope it helps!