a : b = 9:4 and 10b = 7c
work out a:c in its simplest form
Hmm, let me try this one.
We know that a:b=9:4, and 10b=7c, so that means b:c=10:7
c:b=7:10 Find the LCM of 4 and 10, which is 20.
Thus, the answer is 45:14