Question 1086282

A school has 630 students. The ratio of the number of boys to the number of girls is 3:2. This ratio changes to 7:5 after the admission of 90 new students. Find the number of newly admitted boys.
<pre>Number of boys, initially: {{{matrix(1,3, (3/5) * 630, "=", 378)}}}
With 90 students being added, the number of students become: 720 (630 + 90)
Number of boys after new admissions: {{{matrix(1,3, (7/12) * 720, "=", 420)}}}
Number of newly admitted boys: {{{highlight_green(matrix(1,3, 420 - 378, "=", highlight(42)))}}}
It is that easy! Nothing COMPLEX/CONFUSING!