Step-by-step explanation:
let's do this in 2 steps :
1. go for 1×10⁴ math problems
2. multiply that result by 5 to fully cover 5×10⁴
1.
3.5×10^-5 × 1×10⁴ = 3.5×10^-1
2.
5 × 3.5×10^-1 = 16.5×10^-1 = 1.65×10⁰
so, the computer needs 1.65×10⁰ or simply 1.65 seconds.