(3 A sum of money doubles itself in 6 years. In how many years, it becomes 5 times? ​

In 24 years.

Step-by-step explanation:

Let the sum of money be 100 which amounts to 200 ( doubles itself ) in 6 years time. Interest on 100rs. Is 100. Putting the following in simple interest formula. You get :

Now when 100 will become 5 times i.e 500 the interest will be 400rs.

Putting in simple interest formula:

So, in 24 years, it will become 5 times.

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

69.64%

step-by-step explanation: