Sarah, Bob and Nellie are cousins. Sarah is half the age of Bob. In three years time Nellie will be twice as old as Sarah. Their ages at the moment add to 38 years. Determine the ages of Sarah, Bob and Nellie

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Step-by-step explanation:

Let s, b, n represent the current ages of Sarah, Bob, and Nellie, respectively.

  s = b/2 . . . . . . Sarah is half Bob's age

  2(s+3) = n+3 . . . . in 3 years, Nellie will be twice Sarah's age

  s + b + n = 38 . . . . . their ages now add to 38

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We can rearrange the first two equations to find Bob and Nellie's age in terms of Sarah's. Then we can substitute into the third equation to find Sarah's age.

  b = 2s . . . . . . multiply the first equation by 2

  2s +3 = n . . . . subtract 3 from the second equation and simplify

  s +(2s) +(2s+3) = 38 . . . . substitute for b and n

  5s = 35 . . . . . . . . . . . . subtract 3, collect terms

  s = 7 . . . . . . . . . . . . divide by 5

  b = 2(7) = 14

  n = 2(7) +3 = 17

Sarah is 7, Bob is 14, and Nellie is 17.

answer: -1

step-by-step explanation:

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have