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2 years ago

If you add 20% of a number to the number itself what percent of the result would you have to subtract

Mathematics

1 answer:

Alina [70]2 years ago

5 0

N+ 0.2n = 1.2nn = (1.2n) - (1/6)*(1.2n)
1/6 = 16.667%

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A bakery sells 10 peanut butter cookies for a total of $7.00. Find the unit rate

mariarad [96]

Answer: $0.70 per cookie

Which is the same as saying 70 cents per cookie

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Explanation:

The unit rate is the cost of one cookie. The term "unit" means "one".

10 cookies = 7 dollars

10/10 cookies = 7/10 dollars ...... divide both sides by 10

1 cookie = 0.70 dollars

Since one cookie costs $0.70, the unit rate is $0.70 per cookie or you can say 70 cents per cookie.

6 0

3 years ago

If three prime numbers are randomly selected from the prime numbers less than 30 and no prime number can be chosen more than onc

Dmitry [639]

Answer:

C)30%

Step-by-step explanation:

Prime numbers less than 30 are given below

2,3,5,7,11,13,17,19,23,29

We have to find the probability that sum of three prime numbers selected will be even.

We know that

Sum of any three prime number except 2 will be odd.

Total prime numbers except 2=9

Total prime numbers=10

Probability:P(E)= $\frac{favorable\;cases}{total\;number\;of\;cases}$

Probability of getting sum of three prime numbers selected will be odd= $\frac{9C_3}{10C_3}$

$nC_r=\frac{n!}{r!(n-r)!}$

By using formula

Probability of getting sum of three prime numbers selected will be odd=P(E)= $\frac{\frac{9!}{3!6!}}{\frac{10!}{3!7!}}=\frac{9!}{3!6!}\times \frac{3!\times 7\times 6!}{10\times 9!}$

Probability of getting sum of three prime numbers selected will be odd=P(E)= $0.7$

Probability of getting sum of three prime numbers selected will be even=P(E')=1-0.7=0.3= $0.3\times 100=30$ %

By using formula P(E')=1-P(E)

3 0

2 years ago

Larry and Donna bought a sofa at the sale price of $1,344. The original price of the sofa was $1,920. Find the discount rate

velikii [3]

Answer:

30% discount

Step-by-step explanation:

To find the percent discount write a proportion.

$\frac{1344}{1920}=\frac{x}{100}$

Cross multiply numerator with denominator of each fraction to solve for x.

1344(100) = 1920(x)

134400 = 1920x

70 = x

This means you pay 70% of the price. The discount was 30%.

8 0

2 years ago

Solution to the system of equation -6x+y=-3 and 7x-y=3

djverab [1.8K]

Answer:

X = 0

Y = -3

Step-by-step explanation:

In this situation you would choose elimination.

-6x+y=-3

7x-y=3

---------------

x = 0

plug back in to find y

(-6)(0) + y = -3

0 + y = -3

y = -3

plug in to other equation for double check

7(0) - (-3) = 3

0 + 3 = 3

3 = 3

Hope this helps

3 0

2 years ago

A crystallographer measures the horizontal spacing between molecules in a crystal. The spacing is 14.8 nm . What is the total wi

IrinaK [193]

Answer: 1539.2nm

The space between molecule is going as X-1 function. That mean 1 molecule doesn't have space, 2 molecules have 1 space, 3 molecules have 2 space. Then 105 molecules will be will have 104 space.
Each space is 14.8nm, the total distance would be: 104 space x 14.8 nm/space= 1539.2nm

4 0

2 years ago