Question 590418
If he got x (in £) for his birthday, he spent 10%x={{{(10/100)x=0.1x=(1/10)x}}} to pay of the loan and {{{5/7}}} of the remaining {{{x-0.1x=0.9x=(9/10)x}}} to celebrate.
So, he spent {{{(5/7)(9/10)x}}} to celebrate and {{{(1/10)x}}} to pay of the loan.
Then, he was left with (in £)
{{{x-(1/10)x-(5/7)(9/10)x=156}}} --> {{{x(1-1/10-45/70)=156}}} --> {{{x(70/70-7/70-45/70)=156}}} --> {{{(18/70)x=156}}} --> {{{x=156*70/18}}} --> {{{x=26*70/3}}} --> {{{x=26*70/3}}} --> {{{x=1820/3}}} --> {{{x=606&2/3}}}
The strange thing is the fraction.