2.3 Assuming simple interest, determine Alvin's initial deposit if his account grew to $7700 in four years at an annual interest rate of 3.54%. 2.4 An investment group of 15 college students at Duke University decided to contribute $255 each into a regular savings account. Determine how much would be in the account after four years at a 1.23% annual rate of interest, assuming monthly compounding. 2.5 (Excel) Assuming weekly compounding, how long (in years and months) does it take for $1784 to grow to $2290 with an annual interest rate of 6.11%? a. Find without using Excel b. Find using Excel