Ida scored an average of 74 marks for math and science. She scored an average of 83 marks for math and english. How many more marks did she score in english than in science?
Let's denote the marks Ida scored in math as M, the marks she scored in science as S, and the marks she scored in English as E.
We are given:
(M + S) / 2 = 74
(M + E) / 2 = 83
From the first equation:
M + S = 148
M = 148 - S
Substitute M = 148 - S into the second equation:
(148 - S + E) / 2 = 83
148 - S + E = 166
E = S + 18
Therefore, Ida scored 18 more marks in English than in science.