Maths - Function and Modelling

2008-05-06 6:20 pm

This is a practice question for my maths class, and I really need help.

At a fun park, a motorised toy boat operates for 5 minutes for every dollar coin placed in a meter. the meter will accept a maximum of 120 one-dollar coins.

a.) Write a rule which gives the time od boat operation, B hours, in terms of the number of dollar coins, n.
b.) Sketch the graph of the function and state the domain and range.
c.) How much is in the meter when the boat has operated for 450 minutes?

回答 (1)

用戶157263

2008-05-06 6:51 pm

✔ 最佳答案

a) B = The number of hours that the boat has operated
n = The number of dollar coins in the meter
As 1 dollar coins makes the boat operated 5 min,
so the no. of min that the boat operated = 5n when n dollar coins are in the meter

The rule: B = 5n/60

b) As the meter can only hold up to120 one-dollar coins, so n less than or equal to120.
this implies n is greater than or equal to 0 and n is less than or equal to 120. (the meter can hold nth, but not neg. dollars)
Sub this contraints in the rule, so B is greater than or equal to 0 and is less than or equal to 10.

Range: B is greater than or equal to 0 and is less than or equal to 10.
Domain: n is greater than or equal to 0 and n is less than or equal to 120

c) 450 min = 7.5 hours
Sub this in the rule, so n = 90.
90 dollars are in the meter after the board has operated for 450 min.

參考: Myself

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