Step-by-step explanation:
Let Xb be the no of braclets made
Let Xn be the no of necklaces made
Max Z=250Xb + 500Xn (Objective Function)
Subject to
2Xb + 5Xn <= 625 (rubies)
3Xb + 7 Xn <= 800 ( diamonds)
4Xb + 3 Xn <= 700 (Emeralds)
Xb>=0 (non-negativity)
Xn >= 0 (non negativity
The average speed for the trip is 11 miles per hour, or mph. 99 miles divided by 9 is 11
We are given the following conversion factor:

We are asked to determine how many miles are 140 km. To do that we use the quotient of the conversion factor where the unit we want to convert to is in the numerator and the given unit in the denominator. Since we want to find miles we use the following quotient:

Solving the operations we get:
It takes Chris 10 minutes to drive, so the latest time he can leave home for work would be 7:50 a.m.