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Eduardwww [97]
3 years ago
7

Find how many two digit numbers are divisible by 3

Mathematics
1 answer:
Bad White [126]3 years ago
7 0

I'll use arithmetic series to find it.

First two-digit number divisible by 3 is 12, last such number is 99. Every 3rd number is divisible by 3.

So,

a_1=12\\a_n=99\\d=3\\n=?\\\\a_n=a_1+(n-1)\cdot d\\99=12+(n-1)\cdot 3\\3n-3=87\\3n=90\\n=30

<u>There are 30 such numbers.</u>

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PLZ ANSWER BOTH QUESTIONS
Firdavs [7]

Answer:

8(3) + 10(7) = 94

8b + 10l = y

Step-by-step explanation:

First, lets make an equation to solve for the numbers.

8b + 10l = Total Amount of Money (y)

Plug in the values.

8(3) + 10(7) = 94 is the amount of money he gets if he does 3 hours of babysitting and 7 hours of lifeguarding.

3 0
3 years ago
There are five consecutive odd integers. The sum of the three smallest is 3 more than the sum of the two largest. Find the integ
Cerrena [4.2K]

Answer:

11 13 15 17 19

Step-by-step explanation:

We will solve this word problem using 2k+1 which is one of the general forms of an odd integer.

Let 2k+1 be the first odd integer.

(2k+1) + (2k+3) + (2k +5) =  (2k+7) + (2k +9) + 3 (the +3 is to accommodate for the left side being 3 more than the right)

Solve for k

6k + 9 = 4k + 19

6k - 4k + 9 = 4k-4k + 19

2k + 9 = 19

2k + 9 - 9 = 19 - 9

2k = 10

2k/2 = 10/2

k = 5

To get the first digit in the series plug in 5 for k

2k+1

2(5) + 1

10 + 1 = 11

So our series is 11, 13, 15, 17, 19

Let's test it.

11 + 13 +15 = 39

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So we are correct, the first 3 integers are 3 more that the sum of the last 2.

6 0
3 years ago
One student begins in Cleveland, Ohio, and walks towards Buffalo, New York, a distance of 200 miles. She walks at the rate of 2.
omeli [17]
Ok so student in cleveland walks 2.5 miles away from cleveland every hour from 8
so the distance, x is x=2.5t

the riding one rides 4 hours later, so t-4
11 mph
y=11(t-4)

A. x=2.5t
y=11(t-4)

when do they meet is when the distance when they are equal or when x=y
2.5t=x=y=11(t-4)
solve for t
2.5t=11(t-4)
2.5t=11t-44
-8.5t=-44
divide both sides by -8.5
t=5.17647

answer is 5.18 hours


A.
x=2.5t
y=11(t-4)

B. 5.18 hours

6 0
3 years ago
The admission fee at the Smithsonian Air &amp; Space
mel-nik [20]
A. 1.50c+ 4.00a = 5050 (Money earned)
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6 0
3 years ago
If 4(x-2/3)=-18, what is the value of 2x?
elena-14-01-66 [18.8K]
4(x-2/3) = -18
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4x = -54/3 + 8/3
4x = -46/3
x = -46/3 * 1/4
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2x = -23/2 * 2
2x = -46/2
2x = -23
7 0
3 years ago
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