maths question

Question

nashita average on 4 test is 80%. what does she need on her fifth test to raise her average to 84%

Answer 1

If there are 4 tests averaging 80%, the sum total must be 4*80=320. When we add a 5th test with score r, then the sum will be 320+r and the average will be (320+r)/5=84. So the total score is 5*84=420 and r must be 420-320=100%. So Nashita must get full marks on the 5th test.