# math

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Select the equation that solves this problem:
Eight coins (dimes and nickels) are worth 60 cents. How many dimes are
there?
a. 10d + 25(11 - d) = 170
b. 10d + 25(8 - d) = 170
c. 10d + 5(8 - d) = 60
d. 10d + 5(11 - d) = 60

• math -

C.

d = the number of dimes, while 8-d equals the numbers of nickels, if you multiply the number of each coins by their value ( 10 cents or 5 cents ) and add them, you should get 60

• math -

A nickel is worth 5 cents and a dime is worth 10 cents.

n = numbers of a nickels

d = numbers of a dimes

n + d = 8

n = 8 - d

Value of money :

10 ¢ * d + 5 ¢ * n = 60 ¢

10 d + 5 n = 60

10 d + 5 ( 8 - d ) = 60

Equation c.

10 d + 5 ( 8 - d ) = 60

10 d + 5 * 8 + 5 * ( - d ) = 60

10 d + 40 - 5 d = 60

5 d + 40 = 60

5 d = 60 - 40

5 d = 20 Divide both sides by 5

d = 20 / 5

d = 4

n = 8 - d = 8 - 4 = 4

4 dimes and 4 nickels

4 * 10 ¢ + 4 * 5 ¢ =

40 ¢ + 20 ¢ = 60 ¢

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