SOLUTION: Write an equation or a system of equations that can be used to solve each of the following problems. In each case, state what the variable or variables represent.(solution of the e

Question 197531: Write an equation or a system of equations that can be used to solve each of the following problems. In each case, state what the variable or variables represent.(solution of the equations is not required.)
a) Julie can keypunch a certain number of computer cards in 4 hours. It takes Pat 6 hours to keypunch the same number of computer cards. If Julie and pat work together, how long will it take them to keypunch that number of cards?
b) The sum of the digits of a two-digit number is 7. If the digits are reversed, the new number is two more than twice the original number. Find the original number.
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Write an equation or a system of equations that can be used to solve each
of the following problems. In each case, state what the variable or
variables represent.(solution of the equations is not required.)
:
a) Julie can keypunch a certain number of computer cards in 4 hours.
It takes Pat 6 hours to keypunch the same number of computer cards.
If Julie and pat work together, how long will it take them to keypunch that number of cards?
;
Let t = no. of hrs required when working together
Let the completed job = 1
+ = 1
:
:
b) The sum of the digits of a two-digit number is 7. If the digits are
reversed, the new number is two more than twice the original number.
Find the original number.
:
Two digits; x and y: The number = 10x + y
"sum of the digits of a two-digit number is 7."
x + y = 7
y = (7-x); use for substitution
:
"If the digits are reversed, the new number is two more than twice the original number.
10y + x = 2(10x + y) + 2
10y + x = 20x + 2y + 2
10y - 2y = 20x - x + 2
8y = 19x + 2
RELATED QUESTIONS
Use ratios to write an equation that can be used to solve each of the following problems. (answered by quentin252)

Solve each of the following systems by addition. If a unique solution does not exist,... (answered by stanbon)

A jar of dimes and quarters contains 52 coins. The value of the coins is $8.65. Write and (answered by josgarithmetic)

A buffet sells plates for seniors at $6, adults at $9, and children for free. If 150... (answered by stanbon)

Directions: Write a proportion that can be used to solve each of the following percent... (answered by EdenWolf)

Solve the following system of equations for the unknown variables. 3x + 3y = 3 -3x (answered by MathLover1,mananth,greenestamps,MathTherapy)

On pages 708 � 711, solve the following problems #16: h(x) = | −2x | Absolute (answered by solver91311)