Question

lindsey is 5 years less than half of her fathers age. the sum of their ages is 79. how old is lindsey? create an equation and solve

Answer 1

$Let \: Lindsey's \: father's \: age \: be \: = \: x$

$Then \: Lindsey's \: age = \frac{1}{2} x - 5$

$Sum \: of \: their \: age = 79$

This can be written in an equation as :-

$x + \frac{1}{2} x - 5 = 79$

$To \: find \: out \: Lindsey's \: age \: , let \: us \: first \: find \: out \: the \: value \: of \: x .

$

$1 \frac{1}{2} x - 5 = 79$

$\frac{3}{2} x - 5 = 79$

$\frac{3}{2} x = 79 + 5$

$\frac{3}{2} x = 84$

$x = 84 \div \frac{3}{2}$

$x = 84 \times \frac{2}{3}$

$x = \frac{168}{3}$

$x = 56$

$Lindsey's \: father's \: age = 56$

$Lindsey's \: age = 28 - 5$

$Lindsey's \: age = 23$

∴Lindsey's age is 23 .