Betty,Connie,Danny and Emmie spent a total of $1590 on a shopping spree. Danny spent 1/3 the amount spent by Betty . Connie spent $240. The total amount spent by Betty and Connie was $120 less than the total amount spent by Danny and Emmie.
(a) How much did Betty and Connie spend altogether?
(b) How much did Emmie spend?
Posted by Isaac Tan (5f2011)
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My solution:
Draw a combination of comparison and part-whole model:
Anchor on any proportional relationships (ie. statements like the "D is 1/3 of B", or "B is 3 times of D")
. B C($240)
. / \ / \ $120 }
. |-----|-----|-----|------------|/ \ }
. |-----|--------------------------------| } $1590
. \ / \ / }
. D E }
(a) B + C --> ( 1590 - 120 ) / 2 = 735 ($)
B --> 735 - 240 = 495
D --> 495 / 3 = 165
(b) E --> 735 + 120 - 165 = 690 ($)
