Answer:
120 seconds (2 minutes)
Explanation:
Standard time = normal time + allowances
The normal time is computed using the following formula
normal time = observed time X ratings/100
observed time mean = (84+76+80+84+76)/5 = 80
A person who is 25% faster has a rating of 125%
normal time = 80 X 125/100 = 100 seconds
Allowances is calculated as a percentage of normal time
Allowance = 80 X 20/100 = 20 seconds
Standard time = 100 + 20 = 120 seconds