Cynthia invests some money in a bank which pays 5% compound interest per year. She wants it to be worth over £8000 at the end of 3years.
What is the smallest amount to nearest pound she can invest?

£6,910.70

Step-by-step explanation:

The computation of the amount invested is given below:

As we know that

Amount = Principal × (1 + rate of interest)^number of years

£8000 = Principal × (1 + 0.05)^3

£8000 = Principal × 1.05^3

£8000 = Principal × 1.157625

So, the principal amount is

= £8000 ÷ 1.157625

= £6,910.70

rick has $1400 and sally has $1500

step-by-step explanation:

to find amount of money rick has after 10 years :

principal = $1000 , time = 10 years , rate = 4% annually

to find amount of money sally has after 10 years :

her friend gives to pay her $50 per year, therefore money she has after 10 years = 50 × 10 = $500

also, sally gets $1000 after 10 years,

therefore, total amount of money sally has after 10 years = 500 + 1000 = $1500

so, after 10 years : rick has $1400 and sally has $1500