P is greater than Q by 60% and greater than R by 30%. The ratio of Q and R is

Let the value of $P$ be a constant. We are given the percentage relations for $P$ with respect to $Q$ and $R$:
1. $P$ is greater than $Q$ by 60%:

$$P=Q+0.60Q=1.60Q⟹Q=\frac{P}{1.60}$$

2. $P$ is greater than $R$ by 30%:

$$P=R+0.30R=1.30R⟹R=\frac{P}{1.30}$$

Now, let's find the ratio of $Q$ to $R$:

$$\frac{Q}{R}=\frac{\frac{P}{1.60}}{\frac{P}{1.30}}=\frac{1.30}{1.60}=\frac{13}{16}$$

Thus, the ratio $Q:R$ is $13:16$.