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3 years ago

Help maths i’m bad at this :)))(

Mathematics

1 answer:

Tju [1.3M]3 years ago

6 0

I suck at math to I’m so so sorry Ask a tutor they will help

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Members of a college chemistry department agree to contribute equal amounts of money to make up a scholarship fund of $280. Then

Zarrin [17]

Answer:

7 members

Step-by-step explanation:

Lets say that the department has n members. If each member contributes with an equal amount x and make a total of $280, we know that:

n*x = 280

Where each one colaborated with:

n*x/n = 280/n

Or what is the same that: (as the n on the left eliminate themselves)

x = 280/n (*)

Now the department hires 3 more members, so we now have n+3 members. And we know that the pass from contributing x to contribute $30 less, it is, x-30 (I omit the $ symbol for simplicity). So, know we have:

x-30 = 280/(n+3)

We can replace x here by the formulation of x we did in the (*) equation:

( 280/n) - 30 = 280/(n+3)

using common denominator:

( 280/n) - 30 n/n = 280/(n+3)

( 280 - 30 n)/n = 280/(n+3)

Cross multiplying the denominators:

( 280 - 30 n)*(n+3) = 280*(n)

280n - 30n^2 + 840 - 90n = 280n

Subtracting 280 n in both sides:

30n^2 + 840 - 90n = 0

Dividing both sides by 30:

-n^2 - 3n + 28 = 0

Factorizing this term (you can notice the factor immediately or solving with baskara resolution, I omit the baskara for simplicity):

-(n + 7)(n - 4) =0

So, n is equal to 4 and -7. As we are dealing with people we can not have -7 people, so we keep only n=4.

So, previous the new hiring there were 4 members, now there are 7.

The used to collaborate with 280/4 = $70, now the collaborate with 280/7=$40, and we see the collaboration decreased in $30.

7 0

3 years ago

To form

Andreas93 [3]

Answer:

40 toothpicks

Step-by-step explanation:

3 times 4 equals 12, so I would multiply 10 times 4 and get 40.

7 0

3 years ago

PLEASE HELP ME THIS.. I REALLY NEED HELP

Colt1911 [192]

9514 1404 393

Answer:

5 hours

Step-by-step explanation:

A quick way to look at this is to compare the difference in hourly charge to the difference in 0-hour charge.

The first day, the charge is $3 more than $12 per hour.

The second day, the charge is $12 less than $15 per hour.

The difference in 0-hour charges is 3 -(-12) = 15. The difference in per-hour charges is 15 -12 = 3. The ratio of these is ...

$15/($3/h) = 5 h

The charges are the same after 5 hours.

If you write equations for the charges, they will look like ...

y1 = 15 + 12(x -1)

y2 = 3 + 15(x -1)

Equating these charges, we have ...

15 +12(x -1) = 3 + 15(x -1)

12x +3 = 15x -12 . . . . . . . . eliminate parentheses

15 = 3x . . . . . . . . . . add 12-12x

x = 15/3 = 5 . . . . . . divide by 3

You might notice that the math here is very similar to that described in words, above.

The charges are the same after 5 hours.

6 0

3 years ago

What is 8.3x10^-9 in standard form?

wariber [46]

.0000000083

( eight zeros.)

6 0

3 years ago

Find f(3) for f(x) = 1/2(4)^x A. 8 B. 32 C. 6 D. 64

Elza [17]

1/2 (4)^3

1/2 x 64

32

7 0

3 years ago

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