For this case what we have to take into account is the following variable:
x = represent the unknown number
We now write the following inequality:
"four times the sum of number and 15 is at least 20"
4 (x + 15)> = 20
We clear the value of x:
(x + 15)> = 20/4
(x + 15)> = 5
x> = 5 - 15
x> = - 10
The solution set is:
[-10, inf)
Answer:
all possible values for X are:
[-10, inf)
1st one is true and second one false.
If there are 12 coins under the couch and every coin is either a nickel or a penny and together they are forming 32 cents then the equations which represent the problem will be x+y=12, 0.01x+0.05y=0.32. The correct option is B which is x+y=12, 0.01x+0.05y=0.32.
Given There are 12 coins and total money is 32 cents.
Let the number of pennies be x and the number of nickels be y.
According to question there are 12 coins so the first equation becomes:
x+y=12.
Then we have been told that together they amount to 32 cents.
We know that 1 penny is 1 cent coin and 1 nickel is 5 cent coin so the equation becomes :
1*x+5*x=32
x+5y=32
converting into dollar
0.01x+0.05y=0.32.
Hence the right equations showing the problem of nickel and pennies are x+y=12, 0.01x+0.05y=0.32.
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