You score 64/75 on your first test. after your second test, your teacher tells you your test average is 88%

First you need to divide 64 by 75 and then multiply by 100 which is 85.3% which then you need to find the average of the 2 which will be (85.3+x)/2=88 where x= the value of the second test.

Then you will need to isolate the x with the following steps:

90.66%

Step-by-step explanation:

let x be the second test score,

0.5( 64/75 + x ) = 0.88

solve for x

x = 0.88 * 2 - 64/75 = 0.906666

which is equivalent to 90.6666... %

check the picture below.