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# Mathematics

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The ratio of the number of pencils to the number of erasers in a box was 12 : 7. Each pencil cost \$0.80. Each eraser cost 1/4 the price of each pencil. Ali paid a total of \$99 for the box of pencils of erasers.
(a) How many pencils were there in the box?
(b) Ali gave an equal number of pencils and erasers to his sister and had a total of 131 pencils and erasers left. How many erasers did he give to his sister?

Jul 8, 2021

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Each pencil = \$0.80

Each eraser = 1/4 * \$0.80 = \$0.20

Each box = pencils  :  erasers  = 12 : 7

= \$99

(a)  \$0.80 * 12 = \$9.60  (pencils)

\$0.20 * 7 = \$1.40  (erasers)

\$9.60 + \$1.40 = \$11

\$99 ➗ \$11 = 9 sets

12 * 9 = 108 pencils

(b) 7 * 9 = 63 erarsers  (Ali have)

108 + 63 = 171  (pencils & erasers)

171 - 131 = 40  (Ali gave)

40 ➗ 2 = 20  (Erasers Ali gave  to sister)

Jul 8, 2021

#1
+2

Each pencil = \$0.80

Each eraser = 1/4 * \$0.80 = \$0.20

Each box = pencils  :  erasers  = 12 : 7

= \$99

(a)  \$0.80 * 12 = \$9.60  (pencils)

\$0.20 * 7 = \$1.40  (erasers)

\$9.60 + \$1.40 = \$11

\$99 ➗ \$11 = 9 sets

12 * 9 = 108 pencils

(b) 7 * 9 = 63 erarsers  (Ali have)

108 + 63 = 171  (pencils & erasers)

171 - 131 = 40  (Ali gave)

40 ➗ 2 = 20  (Erasers Ali gave  to sister)

apsiganocj Jul 8, 2021