40 boys and 68 girls
let's start with variables and an equation.
boys: x
girls: 2x - 12
and we know that boys and girls make up the class. so let's add the two expressions.
x + 2x - 12 = 108
3x - 12 = 108
+ 12 + 12
3x = 120
x = 40 boys
BUT x is only the number of BOYS in the class. so we have to find girls now. let's plug in our value of x into the girls' equation.
2x - 12 = # of girls
2(40) -12 = # of girls
80 - 12 = # of girls
68 girls
let's check our answer!
68 + 40 does in fact add to 108, therefore our answer is correct.
Answer:
question 21 is x= 30
Step-by-step explanation:
when you multiply 7 by 5 you get 35 which is on the bottom side. So, to get x you multipy 6 and 5 and that equals 30.
<span>The probability that a house in an urban area will develop a leak is 55%. if 20 houses are randomly selected, what is the probability that none of the houses will develop a leak? round to the nearest thousandth.
Use binomial distribution, since probability of developing a leak, p=0.55 is assumed constant, and
n=20, x=0
and assuming leaks are developed independently between houses,
P(X=x)
=C(n,0)p^x* (1-p)^(n-x)
=C(20,0)0.55^0 * (0.45^20)
=1*1*0.45^20
=1.159*10^(-7)
=0.000
</span>
Answer:
a^7/b^6
Step-by-step explanation:
Move the decimal so there is one non-zero digit to the left of the decimal point. The number of decimal places you move will be the exponent on the 10. If the decimal is being moved to the right, the exponent will be negative. If the decimal is being moved to the left, the exponent will be positive.
Answer: 9.8 × 10 (4 squared)
