Explanation:
x = hotel charge before tax in 1st city
y = hotel charge before tax in 2nd city
y = x + 1500
x×0.08 + y×0.05 = 692.5
why ?
a% of b = b×a/100
why ?
b = 100%
1% = 100%/100 = b/100
a% = a×1% = a×b/100 = b×a/100
so, e.g. 8% of something is that something multiplied by 8/100 or 0.08
now, we are using the first equation in the second equation :
x×0.08 + (x + 1500)×0.05 = 692.5
x×0.08 + x×0.05 + 1500×0.05 = 692.5
x×0.13 + 75 = 692.5
x×0.13 = 617.5
x = 617.5 / 0.13 = $4,750
y = x + 1500 = 4750 + 1500 = $6,250
the hotel charge before tax in the first city : $4,750
the hotel charge before tax in the second city : $6,250