Answer:
45%
Step-by-step explanation:
9/20=0.45 (Divide it first), 45/100=45% (45/100 because 100 makes 1 whole -all 20 cards-)
Answer:
20 minutes
Step-by-step explanation:
Remember that

we know that
Hector has 3/4 hour to spend his homework
Convert to minutes

so
1) He wants to spend 1/3 of this time on math homework
To find out the time on math homework, multiply 45 minutes by 1/3

2) He wants to spend 10 minutes of his time on reading homework
3) He wants to spend the remaining time on science homework
The time spend on math homework plus the time spend reading homework, plus the time spend on his science homework must be equal to 45 minutes
Let
x ----> the time spend on his science homework

Solve for x

11 and 12
7 and 512
12 and 10
0 and 78
left side numerator
right side denominator
B.yuri divided by n instead of n-1
50. 2x50 = 100. To be safe I would go with any number Between 50 and 100