word problem about iterestv

Question

I'm in algebra 1 and I'm learning with a table with quantity, rate and value

A team of cancer researchers received a grant of $300000 to be used for cancer research. They deposited some in a 10% simple interest account and the remainder in a 8.5% annual simple interest account. How much is deposited in each account if the annual interest is $28,500?

Answer 1

let's consider

 

Deposited in 10 % interest a/c = x

 

 deposited in 8.5% a/c = 300000-x

 

So interest earn from 10% a/c = x*10%=x*0.1 = 0.1x

 

interest earn from 8.5% a/c =(300000-x)*8.5% = (300000-x)*0.085 = 25500 -0.085x

 

So

 

0.1x + 25500 -0.085x = 28500

 

0.015x =3000

 

x = 200000

 

Deposited in 10 % interest a/c = x= $200000

deposited in 8.5% a/c = 300000-x = 300000- 200000=$100000

 

 

 

Answer 2

a + b = 300,000

.1a + .085b = 28,500

 

a = 300,000 - b

.1(300,000 - b) + .085b = 28,500

30,000 - .1b + .085b = 28,500

1500 = .015b

b = 100,000

 

a = 300,000 - 100,000 = 200,000