Whitney has a coin jar with a small collection of nickels and dimes. there are 69 coins in the jar. they have a value of $5.90. how many nickels and dimes are in the jar? use substitution to solve.

The number of nickels in the  jar is 20.

The number of dimes in the jar is 49.

Step-by-step explanation:

Let us assume the total number of nickels = x

The total number of dimes  = y

Total coins = 69 coins

⇒x + y =  69

Now as we know:

      1 Nickel = $0.05

and 1 Dime = $0.10

⇒ The value of x nickels = x ( $0.05)  = 0.05 x

and The value of y nickels  =  y ( $0.10)  = 0.10 y

Total amount in jar = $5.90         ⇒0.05 x + 0.10 y =  $5.90

So, the given system of equation is

x + y =  69    (1)

0.05 x + 0.10 y =  5.90   (2)

Substitute the value of y =  69 - x in (2) , we get:

0.05 x + 0.10 y =  5.90   ⇒ 0.05 x + 0.10 ( 69 - x)  = 5.90

or, 0.05 x +  6.9 - 0.10 x = 5.90

or, - 0.05 x = -1.00

⇒ x = 1/0.05 = 20, or x = 20

⇒ y =  69 - x  = 69 - 20  = 49

Hence the number of nickels in the  jar is 20

and the number of dimes in the jar is 49.

step-by-step explanation:

the true ones are a b and d