Question and Answers Forum

All Questions      Topic List

Others Questions

Previous in All Question      Next in All Question      

Previous in Others      Next in Others      

Question Number 33753 by 255ketto last updated on 23/Apr/18

Answered by MJS last updated on 23/Apr/18

now child′s age x mother′s age 4x five years ago child′s age x−5 mother′s age 4x−5 (x−5)(4x−5)=175 x^2 −((25)/4)x−((75)/2)=0 x=((25)/8)±(√(((25^2 )/8^2 )+((75)/2)))=((25)/8)±((55)/8) x_1 =−((15)/4) is no valid age x_2 =10 child is 10 mother is 40

$$\mathrm{now} \\ $$$$\mathrm{child}'\mathrm{s}\:\mathrm{age}\:{x} \\ $$$$\mathrm{mother}'\mathrm{s}\:\mathrm{age}\:\mathrm{4}{x} \\ $$$$\mathrm{five}\:\mathrm{years}\:\mathrm{ago} \\ $$$$\mathrm{child}'\mathrm{s}\:\mathrm{age}\:{x}−\mathrm{5} \\ $$$$\mathrm{mother}'\mathrm{s}\:\mathrm{age}\:\mathrm{4}{x}−\mathrm{5} \\ $$$$\left({x}−\mathrm{5}\right)\left(\mathrm{4}{x}−\mathrm{5}\right)=\mathrm{175} \\ $$$${x}^{\mathrm{2}} −\frac{\mathrm{25}}{\mathrm{4}}{x}−\frac{\mathrm{75}}{\mathrm{2}}=\mathrm{0} \\ $$$${x}=\frac{\mathrm{25}}{\mathrm{8}}\pm\sqrt{\frac{\mathrm{25}^{\mathrm{2}} }{\mathrm{8}^{\mathrm{2}} }+\frac{\mathrm{75}}{\mathrm{2}}}=\frac{\mathrm{25}}{\mathrm{8}}\pm\frac{\mathrm{55}}{\mathrm{8}} \\ $$$${x}_{\mathrm{1}} =−\frac{\mathrm{15}}{\mathrm{4}}\:\mathrm{is}\:\mathrm{no}\:\mathrm{valid}\:\mathrm{age} \\ $$$${x}_{\mathrm{2}} =\mathrm{10} \\ $$$$\mathrm{child}\:\mathrm{is}\:\mathrm{10} \\ $$$$\mathrm{mother}\:\mathrm{is}\:\mathrm{40} \\ $$

Terms of Service

Privacy Policy

Contact: info@tinkutara.com