A bank offers 5% compound interest per half year. A customer deposits Rs 4800 each on 1
st
January and 1
st
July of a year. At the end of the year, the amount he would have gained by way of interest?

The interest rate per half-year is 5%.
For the deposit made on 1
st
January:
This amount remains in the bank for two half-years (until the end of the year).
Amount at the end of the year:

A
1
​
=4800×(1+
100
5
​
)
2
=4800×(1.05)
2

A
1
​
=4800×1.1025=5292
Interest gained from the first deposit:

I
1
​
=5292−4800=482
For the deposit made on 1
st
July:
This amount remains in the bank for one half-year.
Amount at the end of the year:

A
2
​
=4800×(1+
100
5
​
)
1
=4800×1.05=5040
Interest gained from the second deposit:

I
2
​
=5040−4800=240
Total Interest Gained:

Total Interest=I
1
​
+I
2
​
=482+240=722
Let's check calculation of 4800×1.1025:
4800×1.1025=5292.
5292−4800=492. (Correction: 4800×0.1025=492)
Total Interest = 492+240=732.

Thus, the total interest gained is Rs 732.