Math
posted by Math on .
I need help with these three problems. I cant figure them out.
3. The difference of two numbers is tripled. The result is decreased by 1. If the lesser of the two numbers is 4 the result is 8.3. Find the greater number.
4. A number increased by 21 is ewuivalent to half the number increased by 18.5. find the number.
11. Kerry comutes 60 mi per day. If she drives 30 mi/h during the morning rush and returns over the same route at 50 mi/h how much time does she typically spend commuting each day.
Please help me and thank you very much!

First set up problems to solve each one assiging variables to each unknown. Remember, you need the same number of problems as you have variables.

Convert the words into one or more mathematical equations. I'll get you going on the first one.
"The difference of two numbers ..."
x  y
"... is tripled."
(x  y) * 3
or equivalently
3(x  y)
"The result is decreased by 1."
3(x  y)  1
"If the lesser of the two numbers is 4 ..."
y = 4, so we have
3(x  4)  1
"the result is 8.3."
3(x  4)  1 = 8.3
"Find the greater number. "
solve the above for x.