3 years ago

She purchased 40% of the copies in the store. She has 80 copies of the cd. How many cd were on sale

1 answer:

8 0

To find the number of CD on sale, we can set an equation.

Let y be the number if CD.

As she bought 40%, the amount she bought= 40%y

The equation:

40%y = 80

0.4y = 80

y = 80÷0.4

y=320

Therefore there were originally 320 CDs.

Hope it helps!

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A brick of mass 4 kg hangs from the end of a spring. When the brick is at rest, the spring is stretched by 3 cm. The spring is t

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Answer:

Step-by-step explanation:

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$ky_0+ky-mg=ma\\mg+ky-mg=ky=ma\\\\ky=m\frac{d^2y}{dt^2}\\\\my''+ky=0$