Question Number 138979 by byaw last updated on 20/Apr/21
Answered by greg_ed last updated on 20/Apr/21
$$\boldsymbol{\mathrm{the}}\:\boldsymbol{\mathrm{granddaughter}}\:\boldsymbol{\mathrm{is}}\:\boldsymbol{{x}}\:\boldsymbol{\mathrm{years}}\:\boldsymbol{\mathrm{old}}.\: \\ $$$$\boldsymbol{\mathrm{then}}\:\boldsymbol{\mathrm{we}}\:\boldsymbol{\mathrm{get}}\:: \\ $$$$\mathrm{10}{x}\:=\:{x}\:+\:\mathrm{54}\:\Rightarrow \\ $$$$\mathrm{9}{x}\:=\:\mathrm{54}\:\Rightarrow \\ $$$${x}\:=\:\mathrm{6} \\ $$$$\boldsymbol{\mathrm{so}}\:\boldsymbol{\mathrm{the}}\:\boldsymbol{\mathrm{grandfather}}\:\boldsymbol{\mathrm{is}}\:\mathrm{60}\:\boldsymbol{\mathrm{years}}\:\boldsymbol{\mathrm{old}}. \\ $$