sorry it won't let me show step by step but your answer is 150x-17
Simply take the numerator (3) and denominator (7) and add them together.
3+7 = 10, which means that the ratio will provide parts that are in multiples of 10 depending on the total
so take 10x = 800
x = 80.
Then multiply this by the numerator and denominator
3*80/7*80 = 240/560.
47 R83
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B because you time 4x4 9 times