Answer:
23 cards.
Step-by-step explanation:
After Monday, Esteban has 12 cards.
After Tuesday, Esteban has 12 + 24 = 36 cards.
He gave to his sister x cards.
36 - x = 13
36 = 13 + x
23 = x
Set up the equation by writing the number of students in the ratio as a fraction:
3/4= (245-x)/x Cross multiply:
3x= 4(245-x) Multiply on right:
3x= 980-4x Add 4x on both sides:
7x= 980 Divide both sides by 7:
x= 140 this is how many girls there are. And:
245-140= 105= boys
Answer:
The correct answer is "(18, 30) minutes".
Step-by-step explanation:
Mean,
= 24
Standard deviation,
= 2
The range of minutes where 99.7% of individuals completed the quiz will be:
= 
On substituting the values, we get
= 
= 
now,
= 
= 
Or,
= 
= 
i.e., 18 to 30 minutes
Answer:
52
Step-by-step explanation: