Answer:40
Step-by-step explanation:This is a variation question
From the statement. Let the mental age be M and the chronological age be C, then
IQ ∝M ∝1/C
⇒ IQ ∝ M/C
Introducing the proportionality constant
IQ = KM/ C
Given : M = 15, C = 30 , 1Q = 20
Substitute the given values into the equation
i.e 120 = K x 15/ 30
120 = k/2
therefore k = 240
substitute k = 240 into the equation, we have
IQ = 240M/C
To find C when IQ is 120 and M is 20, we will substitute into the generated formula
i.e 120 = 240 x 20 / c
120c = 480
C = 480/120
C = 40
Therefore , the chronological age of a person with mental age of 20 and IQ of 120 is 40
Answer:
28 percent
Step-by-step explanation:
To find what percentage of a number another number is, you can basically just divide it, 21/75 then you can multiply it by 100, so 21/75=0.28, and then 0.28*100=28, 21 is 28 percent of 75
Answer:
120 ≤ 20c + 40s
Step-by-step explanation:
(Assuming her name is Kylie, who is giving 40 minute science sessions and 20 minute Chinese sessions.)
The unit for time will be minutes.
Write an equation for time needed for science sessions
40s = t
Write an equation for time needed for Chinese sessions
20c = t
Combine the two equations for the total time.
20c + 40s = total time
She does not want the total time to be more than two hours.
Convert two hours to minutes. There are 60 minutes in an hour.
2h * 60mins = 120 mins
Therefore t ≤ 120. Include this into the equation.
120 ≤ 20c + 40s
Answer:
3.7 or 3.71428571429
Step-by-step explanation:
:/
The second one is correct. 66/300 = x/100
