Answer: The other child is "6 years old".
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Step-by-step explanation:
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Set up the ratio as a fraction:
→ " 2/3 = 4/x " ; Solve for "x" (the age; in "years", of the "other child") ;
Note: GIven the ratios of two children is: 2:3 ; and there is a younger child among the two children; the number "2" would represent the "younger child; since there are 2 (two) children; and there are 2 (two) numbers in the given ratios; and among the 2 (two) numbers given in the ratio — which are: "2" and "3" ; the given number: "2" is LESS THAN the given number "3" ;
As such:
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→ " 2/3 = 4/x " ; Solve for "x" ;
Cross-multiply;
2x = 3*4 ;
2x = 12 ;
Divide each side of the equation by "2" ;
to isolate "x" on one side of the equation; & to solve for "x" ;
2x/2 = 12/2 ;
to get:
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" x = 6 "
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Alternate method:
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Set up the ratio:
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→ " 2/3 = 4/x " ; Solve for "x" ;
Recognize that: "2/3 = 4/6" ; and that: "x = 6" ;
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Alternate method:
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Set up the ratio:
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→ " 2/3 = 4/x " ; Solve for "x" ;
In the "numerator": → " 2 * [what value?] = 4 ? "
→ To find that value: " 4 ÷ 2 = "2 " .
As such: Multiply the given: "3" in the "denominator" by "2" ; to get:
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"3 * 2 = "x" ; ↔ " x = 6 " .
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Answer: The other child is "6 years old".
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Check our answer:
The given ratio: 2/3 =? 4/6 ? Yes!
{You can even check this using a calculator—if you wish.}.
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