Answer:
Lady purchased 12 trinkets costing $0.30 each and 8 trinkets costing $0.65 each.
Step-by-step explanation:
A lady buys total number of trinkets = 20
Cost of each trinket is either $0.30 or $0.65.
Let the number of trinkets is x she purchased for $0.30 and y for $0.65
Then x + y = 20 --------(1)
Since she spends total amount = $8.80
Then the equation will be
0.30x + 0.65y = 8.80 ---------(2)
We replace x = (20 - y) from equation (1) to equation (2)
0.30(20 - y) + 0.65y = 8.80
6 - 0.30y + 0.65y = 8.80
0.35y + 6 = 8.80
0.35y = 8.80 - 6
0.35y = 2.80
y = 
y = 8
Now we put y = 8 in equation (1)
x + 8 = 20
x = 20 - 8
x = 12
Therefore, lady purchased 12 trinkets costing $0.30 each and 8 trinkets costing $0.65 each.
Answer:
C. 2.0 < t < 2.5
Step-by-step explanation:
time = distance / speed
The circumference of the lake is given by ...
C = πd = 2π miles ≈ 6.28 miles
Then Johanna's time is ...
(6.28 mi)/(3 mi/h) ≈ 2.09 h
This time is in the interval (2, 2.5), so matches choice C.
___
<em>Alternate solution</em>
If we take pi to be 3, then this boils down to ...
2×3/3 = 2 . . . hours
Pi is on the order of 5% more than 3, so her time will be on the order of 5% more than 2 hours, or just above 2, but not as great as 2.5 hours. This sort of estimating can get you to the correct answer without a calculator.