Question

The sum of two numbers is 21. 3/4 ofone of the numbers added to 2/3 of the other gives a sum of 15. Find the numbers

Answer 1

a + b = 21

3 a/4 + 2b/3 = 15 or times 12 gives 9 a + 8 b = 15*12 = 180
so
9 a + 9b = 21*9 = 189
9 a + 8 b = 180
-----------------------------subtract
1 b = 9
then a = 21-9 = 12