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Alisiya [41]
3 years ago
6

Mary is 3 years older than Sarah.winifred is twice as old as Mary. Altogether thei ages total 89. How old is Sarah

Mathematics
1 answer:
maria [59]3 years ago
7 0

Answer:

sarah is 20 years old

Step-by-step explanation:

We will represent Mary as m, Sarah as s and wilfred as W

so m= s+3, w= 2m

and s + w + m = 89

substitute m for s+3

so

w=2s + 6 and

2s+3+w=89

substitute w for 2s+6

2s + 3 +2s+6=89

4s+9=89

4s= 80

s=20

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-10 = y/11 - 13<br><br> solve for y
Flauer [41]

Answer:

10=y/11-13

We move all terms to the left:

-10-(y/11-13)=0

-y/11+13-10=0

We multiply all the terms by the denominator

-y+13*11-10*11=0

We add all the numbers together, and all the variables

-1y+33=0

We move all terms containing y to the left, all other terms to the right

-y=-33

y=-33/-1

y=+33

6 0
2 years ago
Read 2 more answers
2. The number of atoms of a particular chemical element is modelled by
____ [38]

9514 1404 393

Answer:

  a) 600

  b) see below

  c) 1.26 hours

Step-by-step explanation:

a) The value of y when x=0 is the coefficient of the exponential term:

  y = 600·3^(-0) = 600·1 = 600

There were 600 atoms to start.

__

b) see attached for a graph

__

c) The graph shows 150 atoms at t = 1.26, about 1.26 hours after the start of time counting.

If you want to find that value algebraically, substitute for y and solve for x. Logarithms are involved.

  150 = 600·3^(-x)

  150/600 = 3^(-x)

  log(1/4) = -x·log(3)

  x = -log(1/4)/log(3) = log(4)/log(3) ≈ 1.2618595

After about 1.26 hours, there were 150 atoms.

6 0
3 years ago
Pls help 15 points to best answer. A ladder leans against a building, making a 70 degree angle of elevation with the ground. The
BaLLatris [955]
The correct answer is 2) 14.2
7 0
3 years ago
Giving Brainliest!
zavuch27 [327]
It is the first option- 12 times one fourth the quotient of 6 and 2
4 0
2 years ago
What is the answer for B and how did you get it ?
Orlov [11]
The length of side b is 52 because using the Pythagorean theorem we know that a² + b² = c². When we plug in the known values we would get 1521 + b² = 4225, and when we subtract 1521 from both sides we would get b = 52.
7 0
3 years ago
Read 2 more answers
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