**Given:**

Total amount of money = 20000000

The interest needed annually = 500000

The annual interest rate in mutual funds = 3%

The annual interest rate in treasury bills = 1%

**Required:**

The fraction of donation to be invested in each investment method.

**Solution:**

Let the fraction of donation which is to be invested in mutual funds be P and the other fraction be Q.

Then P + Q = 1 -------> **Equation 1**

The amount to be invested in mutual funds = 20000000 * P

The amount to be invested in treasury bills = 20000000 * Q

The annual interest from mutual funds = `20000000*P*(3/100)`

= 600000P

The annual interest from treasury bills = 20000000*Q*(2/100)

= 400000Q

But we know the total interest should be 500000.

Therefore,

600000P + 400000Q = 500000 --------**Equation 2**

Solving equation 1 and equation2 would give you,

P = 0.5 and Q = 0.5

The fractions to be invested in mutual funds are 1/2 and in treasury bill is 1/2.

**Therefore, exactly half of the donation should go to mutual funds and other half should go to treasury bills.**

**Checking:**

The amount to be invested in mutual funds = 20000000 * 0.5

= 10000000

The interest from mutual funds = 10000000 * (3/100)

= 300000

The amount to be invested in treasury bills = 20000000 * 0.5

= 10000000

The interest from treasury bills = 10000000 * (2/100)

= 200000

The total interest is = 300000+200000 = 500000

Therefore the answer is correct.

**Final answer:**

Half (1/2) of the donation that is 10 million should be invested in mutual funds and other half that is 10 million should be invested in treasury bills.

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