A(S) + 12 = 3 * A(S), subtracting A(S) from both sides one gets 12 = 2 * A(S). Now dividing both sides by 2 we get A(S) = 12/2 = 6 . Therefore, the age of the sister is 6 years when her brother John is three times as old, that is 18 years.

6 0

3 years ago

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21 Last year Chelsea and Sonya took 236 pictures during Thanksgiving. This year Chelsea and Sonya each took the same amount of p

Leokris [45]

Let 'c' represent the number of pictures Chelsea took.

Let 's' represent the number of pictures Sonya took.

For last year's Thanksgiving, c + s = 236

For this year's Thanksgiving, let 'x' represent the number of photos taken in total. x = c + s, where c and s are two integers that are the same (c = s).

And we know that for both years, c + s + x = 500.

As we know that c + s is already 236 from last year, we can remove c + s from the equation in bold and replace it with 236 instead.

236 + x = 500.

Now we have to isolate the x term.

x = 500 - 236

x = 264.

We know that x = c + s, where c and s are the same, so we can just use one of the variables and double it (so you either get 2c or 2s - it doesn't matter which one you pick because they're both the same).

2c = 264

c = 132

c = s

s = 132.

Both took 132 pictures this year.

4 0

3 years ago