Will give crown tell me why you deserve it

because I am Cool j Cole

Nolan took 100 seconds

Step-by-step explanation:

Topic: One unknown equation

let' s assing some variables

K = time took by kong to complete the mult test

N = time took by Nolan to complete the mult test

you ca express  the time took by Kong in terms of Nolan's taken time like this

K = N - 15%N (15% less)

the problem says that K took 85 seconds so we have that

K = 85 s

let's replace this in the equation

85 = N - 15%N let's Factorize

85 = N(1-15%)

so we have that

N = 85 / (1-15%)  or N = 85 / (1-0.15)

N = 85 / (0.85) = 100 s

So Nolan took 100 seconds to fullfil the mult test