Answer:
31.5 hours studying English
Step-by-step explanation:
2 math hours = 3 english hours
21 math hours = ? english hours
21/2 = 10.5
10.5 * 3 = 31.5
4 nickels and 5 pennies.
5 nickels and 0 pennies
The solution is 
<em><u>Solution:</u></em>
Let us assume,

<em><u>Given system of equations are:</u></em>


<em><u>Rewrite the equation using "a" and "b"</u></em>
2a - 3b = -5 ------------ eqn 1
4a + 6b = 14 -------------- eqn 2
<em><u>Let us solve eqn 1 and eqn 2</u></em>
<em><u>Multiply eqn 1 by 2</u></em>
2(2a - 3b = -5)
4a - 6b = -10 ------------- eqn 3
<em><u>Add eqn 2 and eqn 3</u></em>
4a + 6b = 14
4a - 6b = -10
( - ) --------------------
8a = 4

Substitute a = 1/2 in eqn 1

Now let us go back to our assumed values
Substitute a = 1/2 in assumed values

Substitute b = 2 in assumed value

Thus the solution is 
Answer:
y = 55
Step-by-step explanation:
The sum of the angles of a triangle are 180
40 + y+30 + y = 180
Combine like terms
70 +2y = 180
Subtract 70 from each side
2y = 180-70
2y = 110
Divide each side by 2
2y/2 = 110/2
y = 55
Answer:
R = 90
Step-by-step explanation:
Triangles will always equal 180 degrees. If you add 61 + 29 = 90. If two of the three angles already equal 90 degrees, then you would subtract 180 - 90. Therefore, the remaining angle would have to be 90 degrees.