KJSEA 2025 Maths Q13 — Mobile Money Charges (Grade 9)

KJSEA 2025 Grade 9 Numbers

Published

The Question

“Loymer had 4,000 shillings in his mobile money account. He sent 1,500 shillings to his sister and then withdrew 800 shillings. Using the charges table (where sending 1,001 to 2,500 costs 30 shillings and withdrawing 501 to 1,000 costs 28 shillings), how much money did he remain with?”

1

Find the charge for sending 1,500

Look up the amount sent in the charges table. The sent amount of 1,500 shillings falls inside the range from 1,001 to 2,500 shillings, so the charge for that transaction is 30 shillings. Always match the amount to the correct row before reading off the fee.

1,001≤1,500≤2,500  ⇒  charge=301{,}001 \le 1{,}500 \le 2{,}500 \;\Rightarrow\; \text{charge} = 30
2

Find the charge for withdrawing 800

Now do the same for the withdrawal. Withdrawing 800 shillings falls inside the range from 501 to 1,000 shillings, so that transaction is charged 28 shillings. Sending and withdrawing use different rows, so each has its own fee.

501≤800≤1,000  ⇒  charge=28501 \le 800 \le 1{,}000 \;\Rightarrow\; \text{charge} = 28
3

Subtract every outflow from the starting balance

Everything that leaves the account must be taken away from the 4,000 shillings he started with. That means the 1,500 he sent, the 30 charge on it, the 800 he withdrew, and the 28 charge on that. Adding all these outflows and subtracting them from 4,000 gives the balance.

4,000−1,500−30−800−284{,}000 - 1{,}500 - 30 - 800 - 28
=4,000−2,358=1,642= 4{,}000 - 2{,}358 = 1{,}642

Final Result

Loymer remained with 1,642 shillings, which is option A.

Why this method works

Every action on the account either adds money or removes it. Here nothing was received, so both the amounts moved (1,500 sent and 800 withdrawn) and the fees for moving them (30 and 28) reduce the balance. The charges depend on which band the transaction amount falls into, so reading the table correctly is the key step; once each fee is known, the balance is simply the opening amount minus the total of all four outflows.

✓

Total taken out is 1,500 + 30 + 800 + 28 = 2,358, and 4,000 - 2,358 = 1,642, confirming the answer.