MHB What Are the Solutions to the System of Inequalities for Target Heart Rate?

AI Thread Summary
The discussion focuses on determining the target heart rate for exercise based on a person's age using the formula 220 - x, where x represents age between 20 and 70. The American Heart Association recommends maintaining a heart rate between 50% and 85% of the maximum heart rate during exercise. Participants are tasked with creating a system of inequalities to define this target heart rate region. They explore calculations for 50% and 85% of the maximum heart rate, leading to the inequalities 110 - 0.5x ≤ heart rate ≤ 187 - 0.85x. Clarifications are sought regarding the interpretation of solutions within the context of age and heart rate.
mathland
Messages
33
Reaction score
0
One formula for a person’s maximum heart rate is 220 − x, where x is the person’s age in years for
20 ≤ x ≤ 70. The American Heart Association recommends that when a person exercises, the person should strive for a heart rate that is at least 50% of the maximum and at most 85% of the maximum.

(a) Write a system of inequalities that describes the exercise target heart rate region.

I need someone to get me started here.

(b) Find two solutions of the system and interpret their meanings in the context of the problem.

What exactly is part (b) asking for? Is part (b) asking for the value(s) of x?
 
Mathematics news on Phys.org
Here's a start:
(a) What is 50 percent of 220 - x? What is 85 percent of 220 - x?

-Dan
 
topsquark said:
Here's a start:
(a) What is 50 percent of 220 - x? What is 85 percent of 220 - x?

-Dan

(A)0.50(220 - x) = 110 - 0.50x

(B)

0.85(220 - x) = 187 - 0.85x
 
mathland said:
(A)0.50(220 - x) = 110 - 0.50x

(B)

0.85(220 - x) = 187 - 0.85x
Good! So what's the range of values this could take? (Hint: What's the smallest value of x?)

-Dan
 
Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes. I have seen that this is an important subject in maths My question is what physical applications does such a model apply to? I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...
Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Back
Top