Briony invests some money. Interest is paid on the money at a rate of 2% per annum for the first year and 1% per annum for the second year. After two years, the investment is worth £8653.68 How much did Briony invest?

Brionny invested £8400.

Step-by-step explanation:

Simple Interest

This is a simple interest problem.

The simple interest formula is given by:

In which E is the amount of interest earned, P is the principal(the initial amount of money), I is the interest rate(yearly, as a decimal) and t is the time.

After t years, the total amount of money is:

In this question:

We divide in two intervals, the first year and the second year. We have to know that the amount after the end of the first year is the principal at the start of the second year.

First year:

Amount of 2% interest, during 1 year.

So the interest earned is:

The total amount at the end of the first year is:

Second year:

We have that:

The interest earned is of:

The total amount is:

After two years, the investment is worth £8653.68 How much did Briony invest?

So

Brionny invested £8400.

need more information

step-by-step explanation:

there are 70 more legs than eyes at the dog show (196 – 126 = 70). dogs have two more legs than eyes, and humans have the same number of legs as eyes. thus 70 is twice the number of dogs at the show, so the number of dogs is half of 70, which is 35. to get the number of humans, subtract 35 from 63: 63 – 35 = 28.

step-by-step explanation: