Express the average age of three sisters in the terms of the age of the firstborn ( in years) if the second was born 3 years after the first and the third was born 2 years after the second
Answers
Answer:
15 + 15 + 15 = 45
15 + 15 + 15 = 45x + x + x = 45
15 + 15 + 15 = 45x + x + x = 45You know 2 of the x’s. 15 and 12.
15 + 15 + 15 = 45x + x + x = 45You know 2 of the x’s. 15 and 12.12 + 15 + x = 45
15 + 15 + 15 = 45x + x + x = 45You know 2 of the x’s. 15 and 12.12 + 15 + x = 4527 + x = 45
15 + 15 + 15 = 45x + x + x = 45You know 2 of the x’s. 15 and 12.12 + 15 + x = 4527 + x = 45Move the 27 to isolate x. Use subraction.
15 + 15 + 15 = 45x + x + x = 45You know 2 of the x’s. 15 and 12.12 + 15 + x = 4527 + x = 45Move the 27 to isolate x. Use subraction.x = 45 - 27
15 + 15 + 15 = 45x + x + x = 45You know 2 of the x’s. 15 and 12.12 + 15 + x = 4527 + x = 45Move the 27 to isolate x. Use subraction.x = 45 - 27x = 18
Another way,
15 15 15 averages 15. We know this.
15 15 15 averages 15. We know this.12 15 x also averages 15.
15 15 15 averages 15. We know this.12 15 x also averages 15.if 12 is 3 less than 15, and one of your answers IS 15, your other answer is 3 higher than 15.
15 15 15 averages 15. We know this.12 15 x also averages 15.if 12 is 3 less than 15, and one of your answers IS 15, your other answer is 3 higher than 15.12 15 18.
15 15 15 averages 15. We know this.12 15 x also averages 15.if 12 is 3 less than 15, and one of your answers IS 15, your other answer is 3 higher than 15.12 15 18.12 (15–3), 15, 18 (15+3)
15 15 15 averages 15. We know this.12 15 x also averages 15.if 12 is 3 less than 15, and one of your answers IS 15, your other answer is 3 higher than 15.12 15 18.12 (15–3), 15, 18 (15+3)
The average age of three sisters in the terms of the age of the firstborn is (3x +5)/3
Given:
The second was born 3 years after the first
The third was born 2 years after the second
To find:
Express the average age of three sisters in the terms of the age of the firstborn ( in years)
Solution:
Let x be the age of first born
Given that second was born 3 years after
Age of second born = (x+3)years
Third was born 2 years after second
Age of third born = (x+3+2) = (x+5) years
Ages of three sisters are ( in terms of first born) x, (x+3) and (x+5)
Average of their ages = (Sum of ages)/ 3
= (x +x+3+x+5) /3 = (3x +5)/3
The average age of three sisters in the terms of the age of the firstborn is (3x +5)/3
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