SOLUTION: The formula R= -0.075t + 3.85 can be used to predict the world record in the 1500 meter run, t years after 1930. Determine an inequality that identifies the years in which the worl

Algebra ->  Inequalities -> SOLUTION: The formula R= -0.075t + 3.85 can be used to predict the world record in the 1500 meter run, t years after 1930. Determine an inequality that identifies the years in which the worl      Log On


   

Question 275780: The formula R= -0.075t + 3.85 can be used to predict the world record in the 1500 meter run, t years after 1930. Determine an inequality that identifies the years in which the world record will be less than 3.7 minutes. Solve for t.
Found 2 solutions by ankor@dixie-net.com, checkley77:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The formula R= -0.075t + 3.85 can be used to predict the world record in the 1500 meter run, t years after 1930. Determine an inequality that identifies the years in which the world record will be less than 3.7 minutes. Solve for t.
:
-0.075t + 3.85 < 3.7
-0.075t < 3.7 - 3.85
-0.075t < -.15
Multiply -1 to get rid of the negatives, this reverses the inequality sign
.075t > .15
t > .15%2F.075
t > 2 yrs
:
World record will be less that 3.7 min after 1932

Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
R= -0.075t + 3.85
3.7>-.075t+3.85
.075t>3.85-3.7
.075t>.15
t>.15/.075
t>2 years after 1930 or the year 1932 the record will be 3.7 minutes.
Proof:
Let t=2.1.
3.7>-.075*2.1+3.85
3.7>-.1575+3.85
3.7>3.6925