500 in a 3x to 7x ratio
3x + 7x = 500
10x = 500
x = 50
500 can be put in a 3(50) to 7(50) ratio
which is a 150 to 350 ratio
500 in the ratio of 3 to 7 is 150 to 350.
Also notice how 150 + 350 = 500, so our answer is correct.
Note:
a(b) = ab = a x b = a times b
