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

• The equation is 60 _ 15 _ 3 _ 20 _ 4 = 20, with P=+, Q=-, R=×, S=÷.

• Option (b) QRPS translates to: 60 - 15 × 3 ÷ 20 + 4.

• Following BODMAS, first perform division: 3 ÷ 20 = 0.15.

• Next, perform multiplication: 15 × 0.15 = 2.25.

• Then, perform subtraction: 60 - 2.25 = 57.75.

• Finally, perform addition: 57.75 + 4 = 61.75. Wait, let me re-evaluate the order. BODMAS: Division/Multiplication left to right, then Addition/Subtraction left to right.

• Let's re-calculate 60 - 15 × 3 ÷ 20 + 4.

• Step 1: 15 × 3 = 45.

• Step 2: 45 ÷ 20 = 2.25.

• Step 3: 60 - 2.25 = 57.75.

• Step 4: 57.75 + 4 = 61.75. This does not equal 20.

• Let me check the other options to ensure I haven't misread the key or the question logic. Perhaps the question implies a different order or I made a calculation error.

• Let's check Option (a) SPRQ: 60 ÷ 15 × 3 - 20 + 4. (60/15)=4, 4*3=12, 12-20=-8, -8+4=-4. No.

• Let's check Option (c) QRSP: 60 - 15 × 3 ÷ 20 + 4. Same as (b). Wait, QRPS is Q, R, P, S. QRSP is Q, R, S, P.

• Option (b) is Q, R, P, S: 60 - 15 × 3 + 20 ÷ 4.

• Let's re-read the option letters carefully. (b) QRPS. Q=-, R=×, P=+, S=÷.

• Equation: 60 - 15 × 3 + 20 ÷ 4.

• Step 1: 15 × 3 = 45.

• Step 2: 20 ÷ 4 = 5.

• Step 3: 60 - 45 + 5.

• Step 4: 15 + 5 = 20.

• This matches the result 20.