Zayn took 20% fewer seconds than Selena took to complete his timed multiplication test. Zayn took 90 seconds.
How many seconds did Selena take?

Question

Zayn took 20% fewer seconds than Selena took to complete his timed multiplication test. Zayn took 90 seconds.
How many seconds did Selena take?

Quizplus · Accepted Answer

Zayn took 20% fewer seconds than Selena. So, Zayn took 100% - 20% = 80% as many seconds as Selena.
Zayn took 90 seconds to finish the test. To find the number of seconds Selena took, we need to answer: 90 seconds is 80% of what length of time?
Step 1: Use the percent formula to find the number of seconds required. The percent formula is below:
 11ec0fda_98e2_a489_a67f_cf3b6b9953b5_NR0004_00 We are given the part (90) but are looking for the "whole" that is the time taken by Selena, so that is where we will put x.
 11ec0fda_98e2_a48a_a67f_e740a36ebd21_NR0004_00 Step 2: Cross multiply.
 11ec0fda_98e2_a48b_a67f_b580f7b25615_NR0004_00 Step 3: Simplify the right side of the equation. 90 x 100 = 9000
 11ec0fda_98e2_a48c_a67f_0106bba2d173_NR0004_00 Step 4: Simplify by dividing both sides of the equation by 80.
 11ec0fda_98e2_a48d_a67f_81ccc11f72f6_NR0004_00

Zayn Took 20% Fewer Seconds Than Selena Took to Complete His