**Miss Chee bought some pencils, pens and notebooks. The number of notebooks she bought was 25% of the number of pens. The cost of a pencil, a pen and a notebook was $2, $3 and $7 respectively. The total cost of the pens and notebooks were $418 and the total cost of the pencils and notebooks were $262. How many pencils did Miss Chee buy?**

Pencils (unknown no. of pencils) ----- ? x $2 each

Pens ----- 4 units x $3 each ---- 12 units (of dollars)

NB ----- 1 unit x $7 each ----- 7 units (of dollars)

*("Pens" has been allocated 4 units while "NB" 1 unit because the number of NBs bought is 25% of the number of pens)*

Pens + NB ----- $418

12 units + 7 units ---- $418

19 units ----- $418

**1 unit**------ $418/19 =

**$22**(the all important 1 unit)

Pencils + NB ----- $262

? x $2 + 7 units ------ $262

? x $2 + (7 x $22) ----- $262

? x $2 + $154 ----- $262

? x $2 ----- $262 - $154 = $108

? ---- $108/$2 = 54

**Answer: She bought 54 pencils**

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