Ratios/proportions problem?

enter image source here

2 Answers
Nov 4, 2017

$10.5, $15.75, $0.7 respectively

Explanation:

Given that lb is the unit of pounds.

3 lb = 31 lb
4.5 lb = (9/2)
1 lb
0.2 lb = (1/5)*1 lb

Therefore answers are as follows:
(a) required amount
= #3*($3.50)#
= #$10.5#

(b) required amount
= #9/2*($3.50)#
= #$15.75#

(c) required amount
= #1/5*($3.50)#
= #$0.7#

Another solving method: let $x be the value of n lb candies.
#x/n = 3.50/1#

#(1)x = 3.50n #

#x=3.50n#,
which gives the above calculations.

Nov 4, 2017

3lbs will cost = $10.50#

4.5lbs will cost #= $15.75#

#0.2 lb will cost #= $0.70#

Explanation:

If 1 lb costs $3.50, 2 lbs will cost twice the amount of $3.50 or #2*3.50=$7#

Hence 3lbs will cost #3*3.50 = $10.50#

4.5lbs will cost #=4.5 * 3.50 = $15.75#

#0.2 lb will cost #0.2 * 3.50 = $0.70#