Question 1021347
let e + p + r = t where e is number of erasers, p is number of pencils, r is number of rulers and t is the total number, then
e = (1/6)t
p = (1/2)t + 5
r = t - ((1/6)t + (1/2)t + 5)
:
2.20(t/6) + 3.45(t/2 +5) + 1.70(t - t/6 - t/2 - 5) = 519.15
:
(2.20t/6) + 3.45t/2 +17.25 + 1.70t - 1.70t/6 - 1.70t/2 -8.50 = 519.15
:
multiply both sides of = by 6
2.20t +10.35t +103.5 +10.20t -1.70t -5.10t -51.00 = 3114.9
:
15.95t = 3062.4
:
t = 192
:
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The total items bought is 192
The number of erasers bought is 32
The number of pencils bought is 101 
The number of rulers bought is (192 - 133) = 59
Therefore,
There were (101 - 32) = 69 more pencils bought than erasers
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