Question 50171This question is from textbook Beginning Algebra
: The sum of two numbers is 90. The second is 10 more than 4 times the first. What are the two numbers?
This question is from textbook Beginning Algebra
Answer by junior403(76)   (Show Source):
You can put this solution on YOUR website! The trick to solving this type of word problem is to pick out what we know about each of the variables.
Lets go peice by peice.
The sum of two numbers is 90.
So since we know nothing about either number, lets just call them x and y.
easy enough...
x + y = 90
OK so far?
Now lets look at the next statement to try to find some clues.
The second is 10 more than 4 times the first.
So the second number y is 10 more than 4 times the first x.
So we dont know anything about the first number, but know an awful lot about the second in relation to the first.
lets see...
So, couldn't we say that
the first number x + 4 times the first number x + 10 = 90.
or... x = x and y = 4x + 10.
So...
x + 4x +10 = 90
Now we can just solve for x.
x + 4x +10 = 90
first we can subtract 10 from both sides of the equation.
x + 4x = 80
then we can add the variables
5x = 80
now we simply divide both sides by 5
x = 16.
now in order to find the value of y we just plug in the value for x
If y = 4x + 10 and x = 16 then...
y = 4(16) +10
y = 64 + 10
y = 74
so, x + y = 90
or 16 + 74 = 90
true!
I hope this helps.
Good luck!
What are the two numbers?
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