Answer: He has 6 dimes and 2 nickels.
Step-by-step explanation:
If D is the number of dimes and N the number of nickels, we have that:
He has 8 coins:
D + N = 8
He has $0.70 in total:
D*0.10 + N*0.05 = 0.70
Then we have two equations, now we need to isolate one variable in one of the equations and then replace it in the other, let's isolate D in the first equation:
D = 8 - N
Now we can replace it in the other equation:
(8 - N)*0.10 + N*0.05 = 0.70
0.80 - N*(0.10 - 0.05) = 0.70
-N*0.05 = 0.70 - 0.80 = -0.10
N = 0.10/0.05 = 2
D = 8 - N = 8 - 2 = 6
He has 6 dimes and 2 nickels.
Answer:
The number of nickels he has is 2 .
Step-by-step explanation:
A man has $0.70 consisting of dimes and nickels. He has 8 coin altogether . The number of nickel he has can be calculated below.
let
number of dimes = a
number of nickel = b
a + b = 8.........(i)
Total cost
1 dime = $0.1
1 nickel = $0.05
0.1a + 0.05b = 0.70.........(ii)
a + b = 8.........(i)
0.1a + 0.05b = 0.70.........(ii)
a = 8 - b
insert the value of a in equation(ii)
0.1(8 - b) + 0.05b = 0.70.........(ii)
0.8 - 0.1b + 0.05b = 0.70
0.80 - 0.70 = 0.1b - 0.05b
0.1 = 0.05b
divide both sides by 0.05
b = 0.1/0.05
b = 2
Insert the value of b in equation (i)
a + b = 8.........(i)
a + 2 = 8
a = 8 - 2
a = 6
The number of nickels he has is 2 .