Correct Option
Let P, Q, X, Y, and Z represent the number of notebooks purchased by each friend. Based on the given information, a system of linear equations can be formulated:
- Z = X + 8 (Equation 1)
- P + Q = 21 (Equation 2)
- Q = P - 5 (Equation 3)
- X + Y = 28 (Equation 4)
- P = X + 5 (Equation 5)
To determine the number of notebooks purchased by each individual:
- Substitute Equation 3 into Equation 2:
P + (P - 5) = 21
2P - 5 = 21
2P = 26
P = 13 notebooks. - Substitute the value of P into Equation 3:
Q = 13 - 5
Q = 8 notebooks. - Substitute the value of P into Equation 5:
13 = X + 5
X = 8 notebooks. - Substitute the value of X into Equation 1:
Z = 8 + 8
Z = 16 notebooks. - Substitute the value of X into Equation 4:
8 + Y = 28
Y = 20 notebooks.
The total number of notebooks purchased by all five friends is the sum of their individual purchases:
Total notebooks = P + Q + X + Y + Z = 13 + 8 + 8 + 20 + 16 = 65 notebooks.
Given that each notebook is priced at Rs 40, the total cost of all notebooks is calculated as:
Total cost = Total notebooks × Price per notebook = 65 × 40 = Rs 2,600.
Incorrect Options
Options 2 (Rs 2,400), 3 (Rs 2,360), and 4 (Rs 2,320) are incorrect as they do not match the calculated total cost of Rs 2,600 derived from the given information.