SME
Grade 9 Math · Problem type
A step function: pay by the started hour
Use this for “Parking is $4 for each hour or part of an hour. What do 2.5 hours cost?”
Chart
C(2.5) = 12
This is an example. Type your own values to start a new problem.
$
R
×
H
hours
=
$
C
h
Hours parked
example
Formulas
H
=
h
rounded
up
to
a
whole
number
3 = 2.5 rounded up to a whole number
C
=
R
×
H
12 = 4 × 3
Assumptions
•
Each started hour is charged in full, so the hours are rounded up.
•
The graph is a staircase: flat, then a jump at each whole hour.
•
Each step includes its right end (closed) but not its left end (open).
Step-by-step
WE KNOW
h = 2.5, R = $4
FIND
hours charged (H), cost (C)
Step 1 · Find hours charged (H)
Use H = h rounded up to a whole number
A started hour counts as a whole hour.
H
=
2.5
rounded
up
to
a
whole
number
H
=
3
Step 2 · Find cost (C)
Use C = R × H
Pay the rate for each hour charged.
C
=
4
×
3
C
=
$12
Check
Put the numbers back in. Both sides should match.
3 = 2.5 rounded up to a whole number ✓
12 = 4 × 3 ✓
Topic check
See what you know: 5 questions on this topic
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