Answer:
10c = 20
5c = 5
Step-by-step explanation:
Let x be the number of 10c coins; let y be the number of 5c coins. The total is $2.25, so the amount of 10c and 5c coins will add to that. Simita has 25 coins, so x and y, the number of coins, will have to add to 25. Hence, solve the simultaneous equation.
10x + 5y = 225 (1) - times by 0
x + y = 25 (2) - times by 5
10x + 5y = 225 (1)
5x + 5y = 125 (2)
Then, take equation 2 away from equation 1.
5x = 100
x = 20
Substitute x back into the original equation.
x + y = 25
20 + y = 25
y = 5
Y=15 -4y
+4y +4y
5y=15
÷ ÷
5 5
y=3
The answer is 45 because 45-15=30, therefore x=45.
Answer:
Look in the file, I've drew it there!
Answer:
any score that lies between 88.8 and 97.2 is within one std. dev. of the mean
Step-by-step explanation:
One std. dev. above the mean would be 93 + 4.2, or 97.2. One std. dev. below the mean would be 93 - 4.2, or 88.8.
So: any score that lies between 88.8 and 97.2 is within one std. dev. of the mean.
