Q. If P = +, Q = -, R = ×, S = ÷, then insert the proper notations between the successive numbers in the equation 60_15_3_20_4 = 20:

Explanation : 

1. Map the letters to operations:
P = +
Q = –
R = ×
S = ÷

2. Write down the option QRPS in sequence between the numbers 60, 15, 3, 20, 4:
60 Q 15 R 3 P 20 S 4
→ 60 – 15 × 3 + 20 ÷ 4

3. Apply the usual order of operations (× and ÷ before + and –):
15 × 3 = 45
20 ÷ 4 = 5

So the expression becomes:
60 – 45 + 5

4. Compute left to right:
60 – 45 = 15
15 + 5 = 20

Thus, 60 – 15 × 3 + 20 ÷ 4 = 20, confirming QRPS is correct.