Question

Difficulty: MediumSystems of Linear Equations

A tour guide offers two types of guided tours: a walking tour and a trolley tour. On Saturday, the guide led 33 walking tours and 22 trolley tours, which lasted a total of 88 hours. On Sunday, the guide led 22 walking tours and 44 trolley tours, which lasted a total of 1212 hours. If each walking tour has a duration of ww hours and each trolley tour has a duration of tt hours, what is the total duration, in hours, of 11 walking tour and 11 trolley tour?

  1. A
    2.0
  2. 3.5Answer
  3. C
    4.0
  4. D
    4.25

Answer

The correct answer is 3.5.
The correct answer is 3.53.5. The scenario can be represented by the system of linear equations 3w+2t=83w + 2t = 8 and 2w+4t=122w + 4t = 12. Multiplying the first equation by 22 gives 6w+4t=166w + 4t = 16. Subtracting the second equation from this yields 4w=44w = 4, which simplifies to w=1w = 1. Substituting w=1w = 1 into the first equation yields 3(1)+2t=83(1) + 2t = 8, which simplifies to 2t=52t = 5 or t=2.5t = 2.5. The sum of the durations of one walking tour and one trolley tour is w+t=1+2.5=3.5w + t = 1 + 2.5 = 3.5 hours.

Step-by-Step Solution

1
Represent the given scenarios with a system of linear equations using the variables ww (duration of a walking tour) and tt (duration of a trolley tour).
The system of equations is:
1) 3w+2t=83w + 2t = 8
2) 2w+4t=122w + 4t = 12
This translates the word problem into mathematical equations.
2
Solve the system of equations for ww and tt. For example, multiply the first equation by 22 to align the tt coefficients, and then subtract the second equation from it.
Multiplying the first equation by 22 gives 6w+4t=166w + 4t = 16.
Subtracting the second equation (2w+4t=122w + 4t = 12) from this yields 4w=44w = 4, which simplifies to w=1w = 1.
This eliminates the variable tt to find the value of ww.
3
Substitute w=1w = 1 back into one of the original equations to solve for tt.
Using the first equation: 3(1)+2t=8    3+2t=8    2t=5    t=2.53(1) + 2t = 8 \implies 3 + 2t = 8 \implies 2t = 5 \implies t = 2.5.
This determines the value of the second variable, tt.
4
Calculate the sum of ww and tt to find the total duration of 11 walking tour and 11 trolley tour.
w+t=1+2.5=3.5w + t = 1 + 2.5 = 3.5.
This directly answers the question asked in the problem stem.

Key Concept

Solving a system of linear equations to find a linear combination of variables
Estimated Time:1m 30s
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