It is easier to add two fractions together if you convertb them to the same values. You can convert both of these fractions to 20ths quite easily. 3/4 is equal to 15/20ths and 9/10ths is equal to 18/20ths, Simply add them together to find 15/20 + 19/20 = 34/20 now reduce this to a proper fraction... 1 and 14/20ths which can be simplfied to 1 and 7/10ths.
2/15 + 1 + 7/10 = 11/6
9 tenths
7 20ths as a percentage is 35%.
7 10ths.
0.35
7/20 = 0.35
70%
70%
(30 ÷ 10) × 7 = 21
0.007 or 7/10ths
7/10 = 70%