Can some one tell me how to answer question (c)1 and 2(b) in the additional mathematic project form 5?

Question

(c)Ang, Bakar and Chandran, each decided to open a fixed deposit account of RM10000 for 3 years without any withdrawal.

-Ang keeps the amount at an interest rate of 2.5% per annum for duration of 1 month renewable at the end of each month.

-Bakar keeps the amount at an interest rate 3% per annum for duration of 3 months renewable at the end of every 3 months.

-Chandran keeps the amount at an interest rate of 3.5% per annum for a duration of 6 months renewable at the end of every 6 months

(i) Find the total amount each of them will receive after three years.

(b)If Chandran starts his investment with RM500 instead of RM300 at the same interest rate, calculate on which birthday will the total investment be more than RM25000 for the first time

Answer 1

A = 10,000(1 + .025/12)^36 = 10,778.00
B = 10,000(1 + .03/4)^12 = 10,938.07
C = 10,000(1 + .035/2)^6 = 11,097.02

(1 + .035/2)^n = 25,000/500
(1.0175)^n = 50
n = ln(50)/ln(1.0175) = 225.49 . . . rounded up = 226, divided by 2 = 113 years

Answer 2

Amount of interest Ang will receive:
(RM10,000 * [1 + {2.5%/12}]^36) - RM10,000
RM788.00

Amount of interest Bakar will receive:
(RM10,000 * [1 + {3%/4}^12) - RM10,000
RM938.07

Amount of interest Chandran will receive:
(RM10,000 * [1 + {3.5%/2}^6) - RM10,000
RM1,097.02

b) As regards this problem the data seem not clear to me but I think you mean RM5,000 instead of RM500, else it be a couple of centuries before his investment of RM500 will grow to more than RM25,000. If what you mean is RM5,000 then his investment will be equivalent to RM25,099.84 after 93 semi-annuals or 46 1/2 years.