Ralph is 3 times as old as Sara. In 6 years, Ralph will be only twice as old as Sara will be then.

1 answer:

5 0

R = 3S

R + 6 = 2 (S+6)

Substitute the first equation in the second one:

(3S) + 6 = 2 (S + 6)

3S + 6 = 2S + 12

S + 6 = 12

<u>R = 18
</u>S = 6<u>
</u>
Check:

R is 3 times S now.

In 6 years, R will be (18 + 6) = 24, S will be (6 + 6) = 12.

24 = 2 x 12 yay

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A cylinder with a radius of 12cm and a height of 20cm has the same volume as a cone with a radius of 8cm. What is the height of

ivanzaharov [21]

Answer: 135cm

Step-by-step explanation

Volume of a cylinder = πr²h

Volume of a cone. = 1/3πr²h

The two shapes are both solid shapes.

Since the have same volume, we can then equate the two together and solve for the height of the cone.

Now make H the height and R the radius of the cylinder and h the height and r the radius of the cylinder.

Now equating the two

πR²H = 1/3πr²h

Now substitute for the values now

Multiply through by 3

3πR²H = πr²h

But π is common so it could be obliterated from the equation

3R²H = r²h

3 x 12² x 20 = 8² x h

3 x 144 x 20 = 64 x h

60 x 144 = 64h

8640. = 64h

Therefore

h = 8640/64

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8 0

2 years ago

2/5 x 6/7= I cant figure out this question.

telo118 [61]

Answer:

I got 0.3428571429

Step-by-step explanation:

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4 0

1 year ago

Read 2 more answers

Maureen earned some money doing odd jobs last summer and put it in a savings account that earns 9% interest compounded quarterly

ivolga24 [154]

Answer:

Maureen earned $123.19 doing odd jobs

Step-by-step explanation:

The compound interest formula is given by:

$A(t) = P(1 + \frac{r}{n})^{nt}$

Where A(t) is the amount of money after t years, P is the principal(the initial sum of money), r is the interest rate(as a decimal value), n is the number of times that interest is compounded per unit year and t is the time in years for which the money is invested or borrowed.

In this question:

Compounded quarterly means that $n = 4$