A jar contains nickels and dimes. There are 20 coins in the jar, and the total value of the coins is $1.40. How many nickels and how many dimes are in the jar.
Write the system of equations used to solve this problem. Define the variables.
(Hurry)

Step-by-step explanation:

n and d are the number of nickels and dimes, respectively.

"there are 20 coins"

n+d = 20

d = 20-n

"total value is $1.40"

0.05n + 0.10d = 1.40

0.05n + 0.10(20-n) = 1.40

-0.05n + 2 = 1.40

0.05n = 0.6

n = 12

d = 20-m = 8

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have