P = 78, Q = 87 and R = 17.
If we convert all of them into like fractions by LCM method,
i.e., LCM of 8, 7 and 7 will be 56,
So P = 7×78×7 = 4956
Q = 8×87×8 = 6456
and R = 1×87×8 = 856
We get:
6456 > 4956 > 856
Or
Q > P > R
∴ Q is greater.