Problem Solving, have a go. [SHOW WORKING]?
April 7, 2010 by
Filed under printed skirt
1. Jenny has 3 skirts, 4 blouses, and 3 jumpers. She intends to wear them to work in various combinations. The blue skirt doesn’t go with the green jumper. otherwise any combination of three garments is all right. how many different combinations can Jenny make?
2. 2 planes leave to Sydney at 9am. one flies west to Perth. the other flies eat to Auckland. the westbound plane travels at 425km per hour, and the other at 457km per hour. how long will it take for the two planes to be 3000km apart?
3. Bronwyn arranged to have a design printed on windcheater to raise money for her basketball club. it cost $75 plus $3.50 for each windcheater printed. she recieved a bill for $425 from the printing firm, but the invoice did not state how many windcheaters were printed. she did some calculations and discovered the bill was indeed correct. how many windcheaters were printed?
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3 skirts x 4 blouses x 3 jumpers – 3 combinations that don’t work = 99 combinations
the planes crash because they can’t possibly carry that much fuel
probably around 9000
1.) 3 x 4 x 3 = 36
36 – 3 jumpers = 33<—–Answer
2.) 425x + 457x = 3000
879x = 3000
3.41 hours. <—–Answer
This would be 3 hours and 24 min
3.) 75 + 3.50x = 425
3.50x = 350
x = 10 <—–Answer
Hope this helps!
1.
Call the 3 skirts: A, B, C. A is the blue skirt.
Call the 4 blouses: 1, 2, 3, 4.
Call the 3 jumpers: a, b, c. a is the green jumper.
Possible combinations:
Skirt A:
A1b
A1c
A2b
A2c
A3b
A3c
A4b
A4c
Total: 8
B1a
B1b
B1c
B2a
B2b
B2c
B3a
B3b
B3c
B4a
B4b
B4c
Total: 12
Skirt C:
C1a
C1b
C1c
C2a
C2b
C2c
C3a
C3b
C3c
C4a
C4b
C4c
Total: 12
8 + 12 + 12 = 32
Jenny can make a total of 32 combinations.
Mathematically:
Total possible combinations – Combinations of blue skirt and green jumper = Total combinations Jenny can make.
(3 x 4 x 3) – (1 x 4 x 1) = 36 – 4 = 32
2.
D = distance
r = rate (speed)
t = time
D = rt
Perth bound plane (Dp):
Dp = 425(km/hr)t
Auckland bound plane (Da):
Da = 457(km/hr)t
Since they are travelling in opposite directions, we want to know when Dp + Da = 3000
425(km/hr)t + 457(km/hr)t = 3000km
882(km/hr)t = 3000km
t = 3.40 hrs
t = 3 hrs 24 min.
3.
Let w = # of windcheaters printed
$75 + $3.50w = $425
$3.50w = $350
w = 100
100 windcheaters were printed.