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lara31 [8.8K]
3 years ago
6

Mariana averaged 80 on her first three math exams. The first score was 86. The second score was 74. What was the third exam scor

e?​
Mathematics
1 answer:
Anna71 [15]3 years ago
6 0

The three scores are 86, 74, and an unknown score x. The average (i.e. the sum divided by how many there are) is 80, so we have

\dfrac{86+74+x}{3}=80

Multiply both sides by 3 and you get

160+x=240

Subtract 160 from both sides to get

x=240-160=80

Note: you could solve this exercise very quickly if you notice that the two numbers, 86 and 74, are symmetrical with respect to 80, which is the average. So, the third number must be the average.

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The simple interest on a sum of money for 2 years at 12% per annum is rupees 1380
julia-pushkina [17]

Answer:

5750

710.7

Step-by-step explanation:

Simple interest = principal. * rate * time

Principal (p) = sum of money

1380 = p * 0.12 * 2

1380 = 0.24p

p = 1380 / 0.24

p = 5750 rupees.

The compound interest :

A = P(1 + r/n)^nt

A = final amount

n = number of compounding times per period

t = period

A = 5750(1 + 0.12/2)^2*1

A = 5750(1 + 0.06)^2

A = 5750(1.06)^2

A = 5750 * 1.1236

A = 6460.7

Hence, compound interest is :

Final amount - principal

6460.7 - 5750

= 710.7 rupees

4 0
3 years ago
Weight (g)
navik [9.2K]

Answer:  a) add n+1 to the previous term

               b) add the previous two terms

               d) subtract n+1 from the previous term

               e) multiply the previous term by 3

               f) subtract 2 from previous term then add 5 to the next term

<u>Step-by-step explanation:</u>

a) 1, 3, 6, 10

    ∨  ∨  ∨

  +2 +3 +4           The next term is 10 +5 = 15

b) 1, 2, 3, 5

    ∨  ∨  ∨

  =3 =5 =8        The next term is 5 + 8 = 13

d)  8, 7, 5, 2

      ∨  ∨  ∨

     -1  -2  -3             zThe next term is 2 - 4 = -2

e) 1, 3, 9, 27

     ∨  ∨  ∨

    ×3 ×3 ×3         The next term is 27 × 3 = 81

f) 49, 47, 52, 50, 55

      ∨    ∨    ∨    ∨

     -2   +5   -2   +5      The next term is 55 - 2 = 53

                                    The following term is 53 + 5 = 58

5 0
3 years ago
6.find zeroes by factorisation<br><br>4x2 + 5√2 x - 3​
dangina [55]

-13.213203440000000000000

7 0
4 years ago
Jane is 14 years older than mary. in five years jane will be one less than twice mary's age. what is the sum of jane and mary's
Elenna [48]
Answer =44. Hope this answer is helpful and correct.

4 0
3 years ago
Juan’s classroom is shaped like a rectangle.the room is 40 feet long and 25 feet’s wide which rectangle could be scale drawing o
Svetach [21]

I think there's an image needed to answer this question?

I tried answering without, but you do need the image.

If the length is 40 and the width is 25, the ration of length:width is 40:25.

This can be simplified to 8:5

So the answer would be any drawing with the following dimensions:

1. length 8 ft and width 5 ft

2. length 16 ft and width 10 ft

3. length 24 ft and width 15 ft

4. length 32 ft and width 20 ft

5. length 40 ft and width 25 ft

It's most likely not the last 3 because the sizes are very big, but yeah a scale drawing maintains the same ratio so I assume one of the options for your answers is gonna be one of the answers from 1 - 4 above (5 is the given dimensions so I highly doubt that's the answer)

8 0
3 years ago
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