Let m and j be the current ages of Matthew and Jenny, respectively.
Now, Matthew is 3 times as old as Jenny, so the variables are in the following relation:

In 7 years, both of them will be 7 years older, i.e. their ages will be m+7 and j+7, and Matthew will be twice as old:

Now, remembering that m=3j, we can rewrite the second equation as

So, Jenny is 7 and Matthew is 21 (he's 3 times older).
In fact, in 7 years, they will be 14 and 28, and Matthew will be twice as old.
Answer:
8.75!
Step-by-step explanation:
the answer is x-2.5=6.25
6.25+2.50=8.75
9514 1404 393
Answer:
48°
Step-by-step explanation:
ΔACB is isosceles, so angles A and B have the same measure. The measure of angle C in that triangle is ...
∠C = 180° -2(69°) = 42°
Angle C in ΔCDE has the same measure. Angle D is the complement of that:
∠D = 90° -42° = 48°
_____
The relations we used are ...
- the sum of angles in a triangle is 180°
- base angles of an isosceles triangle are congruent
- vertical angles are congruent
- acute angles in a right triangle are complementary
Answer:



Step-by-step explanation:
Given




Required
The dimension that minimizes the cost
The volume is:

This gives:

Substitute 


Make H the subject


The surface area is:
Area = Area of Bottom + Area of Sides
So, we have:

The cost is:



Substitute:
and 



To minimize the cost, we differentiate

Then set to 0


Rewrite as:

Divide both sides by W

Rewrite as:

Solve for 


Take cube roots

Recall that:







Hence, the dimension that minimizes the cost is:



Outcome - <span>one of the mutually exclusive results of an activity
probability - </span><span>a measure of likelihood of a given result
compound events - </span><span>events involving two or more activities
event - </span><span>a combination of one or more outcomes
independent events - </span>compound events whose outcomes do not affect each other
conditional probability - <span>probability of one event given that another has occurred</span>