Question

A student has passed 60 percent of the 20 quizzes he has written so far successfully. If the student writes 50 quizzes during the year, and passes 80 percent of the remaining quizzes successfully, what is the percent of all successful quizzes for the entire year?

Answer 1

Answer:

72%

Step-by-step explanation:

calculate the quizzes passed for the first 20 quizzes

quizzes first passed = 60% of first 20 quizzes

= (60/100) x 20 = 12 quizzes

now calculate the quizzes passed for the remaining 30 quizzes (50-20 = 30)

quizzes passed later = 80% of next 30 quizzes

= (80/100) x 30 = 24 quizzes

therefore total quizzes passed = 12 +24 = 36 quizzes

percentage of quizzes passed =(total no of quizzes passed / total quizzes written) x 100

percentage of quizzes passed = (36/50) x 100 = 72%

Answer 2

Answer:

72%

Step-by-step explanation:

Start by turning both percentages into decimals.  To do this take the percent and divide it by 100.  So, 60% = 60/100 or .6 and 80% = 80/100 or .8.

Next the student has already completed 20 quizzes.  So, 50-20=30 remaining quizzes.

Quizzes already taken:

$.6*20$

= 12 passed quizzes.

The remaining quizzes for the school year:

$.8*30$

= 24 quizzes

So, Finally add them both together and divide by the total amount of quizzes:

12+24

= 36 passed quizzes

$36/50$

=.72

Now to convert it back into a fraction you multiply the decimal by 100.

$.72*100$

= 72%