Jack has twice as many dimes as quarters. If the total value of the coins is $6.30, how many dimes does he have?
1 answer:
Answer:
Number of dimes = 28
Step-by-step explanation:
Given that:
Worth of coins = $6.30 = 6.30 * 100 = 630 cents
Let,
x be the number of dimes
y be the number of quarters
According to given statement;
x = 2y Eqn 1
10x+25y = 630 Eqn 2
Putting x = 2y in Eqn 2
10(2y) + 25y = 630
20y + 25y = 630
45y = 630
Dividing both sides by 45
Putting y=14 in Eqn 1
x = 2(14)
x = 28
Hence,
Number of dimes = 28
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Answers:
x = 100
y = 25
==============================================================
Explanation:
Angle y and the 25 degree angle are corresponding angle. Because the lines are parallel, this means that y = 25
Check out the attached image. Using a red pen, I extended one of the lines to form a triangle. From the alternate interior angle theorem, we know that one of the angles of the triangle is 75 degrees (alternate interior angles are congruent). Again this stems from the fact that the lines are parallel.
I've also introduced the variable z to help find x. The angles x and z add up to 180 degrees since they form a straight line. So we need to find z before we can find x.
The triangle's angles 25, 75, z add up to 180. Let's solve for z
25+75+z = 180
100+z = 180
z = 180-100
z = 80
Use this to find x
x+z = 180
x+80 = 180
x = 180-80
x = 100
