SOLUTION: I am new to algebra and am having trouble solving the examples my friends submitted for our practice exercises. Can you help me with these two questions. I have tried to solve t

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Question 142209: I am new to algebra and am having trouble solving the examples my friends submitted for our practice exercises. Can you help me with these two questions. I have tried to solve them using the d=r(t) but it doesn't work right, or I am doing it wrong.
1. Maria bicycles 5 km/h faster than Carlos . In the same time it takes Carlos to bicycle 30 km, Maria can bicycle 45 km. How fast does each bicyclist travel?
2. hat size head circum. (to nearest 1/5 inch) head circum to nearest cm
7 3/8 23 1/5 59
??? ????? 58
How do I solve this one? Please help
Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website!
1. Maria bicycles 5 km/h faster than Carlos . In the same time it takes Carlos to bicycle 30 km, Maria can bicycle 45 km. How fast does each bicyclist travel?
:
Let s = C's speed
then
(s+5) = M's speed
:
Write a time equation: Time = dist/speed
;
C's time = M's time
=
Cross multiply:
45s = 30(s+5)
45s = 30s + 150
45s - 30s = 150
15s = 150
s = 10 km/hr is C's speed, 15 km/hr is M's speed
:
:
check solutions by confirming that the times are the same:
30/10 = 3 hr
45/15 = 3 hr
:
:
2. hat size head circum. (to nearest 1/5 inch) head circum to nearest cm
7 3/8 23 1/5 59
-???- ?????- 58
:
Find the relationship of cm to inches: = 2.54 cm in 1 inch
:
Convert 58 cm to inches: = 22.83 inches or 22inches
:
Find the relationship of circumference in inches to hat size
= .318
:
Multiply 22.8 * .318 = 7.24 or 7(hat size)
:
Fill in the table as follows:
7 3/8....23 1/5...59
7 1/4....22 4/5...58
:
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