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3 years ago

What is -1 7/8 + -2 1/4? Please explain why and a step by step :).

Mathematics

1 answer:

olya-2409 [2.1K]3 years ago

8 0

9514 1404 393

Answer:

-4 1/8

Step-by-step explanation:

Many people find it easier to factor out -1, then do the addition. The fractions need a common denominator before they can be added. A suitable denominator that is a multiple of both 4 and 8 is 8.

The fraction 1/4 = (1/4)(2/2) = (1·2)/(4·2) = 2/8.

So, the problem can be rewritten as ...

-(1 7/8 +2 2/8)

= -((1+2) +(7/8 +2/8))

= -(3 +9/8)

The fraction 9/8 is an improper fraction equal to 8/8 +1/8 = 1 1/8. Then the sum is ...

-(3 +1 1/8) = -4 1/8

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Christine has always been weak in mathematics. Based on her performance prior to the final exam in Calculus, there is a 51% chan

Charra [1.4K]

Answer:

a) 0.3270 = 32.70% probability that Christine fails the course

b) 0.3917 = 39.17% probability that she had found someone to help

Step-by-step explanation:

We have these following probabilities:

61% probability that Christine find a coach.

100 - 61 = 39% probability that Christine does not find a coach.

With a coach, a 21% probability of failing.

Without a coach, a 51% probability of failing.

a. What is the probability that Christine fails the course?

21% of 61%(finds a tutor) plus 51% of 39%(does not find a tutor). So

P = 0.21*0.61 + 0.51*0.39 = 0.327.

0.327 = 32.7% probability that Christine fails the course

b. Christine ends up failing the course. What is the probability that she had found someone to help?

This can be formulated by the Bayes formula:

$P(B|A) = \frac{P(B)*P(A|B)}{P(A)}$

In which P(B|A) is the probability of B happening given that A happened and P(A|B) is the probability of A happening given that B happened.

In this question.

P(B|A) is the probability of finding a tutor given that she failed.

P(B) is the probability of finding a tutor. So P(B) = 0.61.

P(A|B) is the probability of failing when finding a tutor. So P(A|B) = 0.21

P(A) is the probability of failing. So P(A) = 0.327.

$P(B|A) = \frac{P(B)*P(A|B)}{P(A)} = \frac{0.61*0.21}{0.327} = 0.3917$

0.3917 = 39.17% probability that she had found someone to help

4 0

3 years ago

when ashley buys 7 postage stamp booklets she gets 140 stamps.she get 60 stamps in three booklets. write an equation to find the

Andreyy89

We can put this information into two equations:

7 booklets = 140 stamps
3 booklets = 60 stamps

Let us then focus on one equation to find the relationship:

7 booklets = 140 stamps

If we put that into a fraction, we get $\frac{7}{140}$ or $\frac{1}{20}$ .

This means that for every booklet, Ashley gets 20 stamps; or rather, each booklet has 20 stamps.

We can then see that this relationship holds true for the second equation as well:

$\frac{3}{60}$ or $\frac{1}{20}$ .

To write a general equation for this relationship using p for the number of postage stamps, and b for the number of booklets:

p = 20b

Where b is equal to p.

5 0

3 years ago

What makes the statement true? 8^-2=?

GREYUIT [131]

I think the correct answer would be 1/64. <span>A </span>negative exponent<span> just means that the base is on the wrong side of the fraction line, so you need to flip the base to the other side. It is calculated as follows:

8^-2 = 1/8^2 = 1/64

Hope this answers the question. Have a nice day.</span>

6 0

3 years ago

Read 2 more answers

A box contains 300 raffle tickets. Only 15 tickets are winning tickets. What is the

Roman55 [17]

Answer:

Step-by-step explanation:

15/300 = 0.05

3 0

2 years ago

A triangle has one side that measures 4x and two sides that measure x + 5 each. Write an

Tamiku [17]