Mary has a collection of nickels and quarters for a total value of 4.90.if she has 42 coins total how many of each kind are there

Let x be the number of nickels and y be the number of quarters.

Then, x + y = 42 --- (1)

It is given that total value = 4.90.

Therefore, 0.05x + 0.25y = 4.9 --- (2)

Multiply (1) by 0.25

0.25x + 0.25y = 10.5 --- (3)

Now, subtract (2) from (3), we get,

0.2x = 5.6

Divide both sides by 0.2.

x = 28

x + y = 42

y = 42 - x

= 42 - 28

= 14

Hence, Mary has 28 nickels and 14 quarters in total.

x =±sqrt(1/3)

step-by-step explanation:

x+4/6x=1/x

multiply each side by 6x to get rid of the fractions

6x*(x+4/6x)=1/x*6x

distribute

6x^2 +4 = 6

subtract 4 from each side

6x^2 +4-4 = 6-4

6x^2 =2

divide by 6

6x^2/6 = 2/6

x^2 = 1/3

take the square root of each side

sqrt(x^2) = ±sqrt(1/3)

x =±sqrt(1/3)