Question 1191871
 A student missed 13 problems on a Physics test and received a grade of 48%.
 If all the problems were of equal value, how many problems were on the test?
 Round off your answer to the nearest integer.
:
let n = number of problems on the test
{{{(n-13)/n}}} * 100 = 48
{{{(n-13)/n}}} = {{{48/100}}}
cross multiply
100(n-13) = 48n
100n - 1300 = 48n
100n - 48n = 1300
52n = 1300
n = 1300/52
n = 25 problems on the test
:
:
Check (he got 12 right)
12/25  * 100 = 48