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2 years ago

Help me with this please

Mathematics

1 answer:

Gala2k [10]2 years ago

6 0

Answer: the answer is -5

Step-by-step explanation:

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A box contains $7.45 in nickels, dimes, and quarters. There are 43 coins in all, and the sum of the numbers of nickels and dimes

kari74 [83]

Answer:

Number of nickels = 6

Number of dimes = 14

Number of quarters = 23

Step-by-step explanation:

Total number of coins = 43

Let number of nickels = n

Let number of dimes = d

Let number of quarters = q

$n+d+q=43 ...... (1)$

Money in n nickels = $n \times 0.05$

Money in d dimes = $d \times 0.10$

Money in q quarters = $q \times 0.25$

Total money = $7.45

$0.05n +0.10d+0.25q = 7.45\\\Rightarrow 5n +10d+25q = 745 .... (2)$

The sum of the numbers of nickels and dimes is 3 less than the number of quarters.

i.e.

$n+d=q-3$

Let us put the value in (1):

$q-3+q=43\\\Rightarrow 2q= 43+3\\\Rightarrow q =23$

Putting the value of q in (1) and (2):

n+d = 20 .... (3)

$5n+10d+575 =745\\\Rightarrow 5n+10d =170\\\Rightarrow n+2d =34 .... (4)$

(4) - (3):

d = 14

Now, from (3):

n = 6

Number of nickels = 6

Number of dimes = 14

Number of quarters = 23

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3 years ago

Y=x+8 Y=-4x-12 Solve each system by substitution

iVinArrow [24]

Answer:

Step-by-step explanation:

hello :

Y=x+8

Y=-4x-12

-4x-12 = x+8

-5x = 20

x = -4

but : y=x+8

so : y=-4+8 = 4

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Answer:

Step-by-step explanation:

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I can't do any more than just tell you want the units are

$\dfrac{mass}{volume}= \dfrac{kg}{m^3}$

m/v = kilograms per meter cubed is the way you would say it.

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