First translate the English phrase "Four times the sum of a number and 15 is at least 120" into a mathematical inequality.
"Four times..." means we're multiplying something by 4.
"... the sum of a number and 15..." means we're adding an unknown and 15 and then multiplying the result by 4.
"... is at least 120" means when we substitute the unknown for a value, in order for that value to be in the solution set, it can only be less than or equal to 120.
So, the resulting inequality is 4(x + 15) ≤ 120.
Simplify the inequality.
4(x + 15) ≤ 120
4x + 60 ≤ 120 <-- Using the distributive property
4x ≤ 60 <-- Subtract both sides by 60
x ≤ 15 <-- Divide both sides by 4
Now that we have the inequality in a simplified form, we can easily see that in order to be in the solution set, the variable x can be no bigger than 15.
In interval notation it would look something like this:
[15, ∞)
In set builder notation it would look something like this:
{x | x ∈ R, x ≤ 15}
It is read as "the set of all x, such that x is a member of the real numbers and x is less than or equal to 15".
Answer: Paul will be 30 years old
Step-by-step explanation:Let the age of her sister be x, then from the given data
=> 4x = 20
=> x = 5 years
The age of her sister is 5 years
In the second case, paul is twice as old as his sister
=> Age of paul = 2(x)
=> Age of paul = 10 years
Paul will be 10 years old when he is twice as old as his sister
Answer:56
Step-by-step explanation:do 180-68, then divide by 2(because the x angles are equal to each other.
I think you would use the equation 2x+1+33+90=180
Answer:
The total cost of the ski hat and the ski boots is $112.35.
Step-by-step explanation:
First, we need to add the prices of the ski hat and the ski boots.
85.50 + 19.50 = $105
Now, we need to find 7% of $105, and then add it to the total.
105 x 0.07 = $7.35
105 + 7.35 = $112.35
Therefore, the total cost of the ski hat and the ski boots is $112.35.
Let me know if this helps!
