Set up 2 equations, with x being the number of weeks:
Shawna = 100 + 5x
Ruben = 75 + 10x ( Use 10 because although he deposits 20 he uses 10, so every week his account only increases by 10).
Set the equations equal to each other and solve for x:
100 + 5x = 75 + 10x
Subtract 5x from both sides:
100 = 75 + 5x
Subtract 75 from both sides:
25 = 5x
Divide both sides by 5:
x = 25/5
X = 5
It will take 5 weeks.
The power rule says that if we have an exponent raised to another exponent, you can just multiply the exponents together.
Step-by-step explanation: