(b) Just go through option and factorize the product into two factors such that the given conditions must satisfy. e.g.,
6=
1×6
2×3
3×2
6×1
It is not true. Again consider option (b)
12=
1×12
2×6
3×4→3×4=12 4×3 6×2→6×2=12 12×1 Now you can see that the rate is being half from 4 to 2 so she can purchase double number of toffees as she was already purchasing on the ground floor. Again to purchase the same number of toffees she had to spend ₹ 2 less than the spending on the ground floor:
Rate
Number of toffee/Re
Total number of toffee
4 ×
3
= 12
2 ×
6
= 12
and if you check other options (c) and (d) they will not satisfy the given conditions.