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tatyana61 [14]
3 years ago
12

Matt says he can find the sum of 45+50 without rewriting it. Explain how you can solve this problem using mental math.

Mathematics
2 answers:
ryzh [129]3 years ago
6 0
Thinking about combining 45 pennies and 50 pennies. How many pennies would you have in total? 95
brilliants [131]3 years ago
6 0
You could add 4+5 and then 5+0 and boom there's your answer!! Hope this helped
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Calculate surface area of pyramids
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A=138.53 in
Use the formula and replace the variables with the length, width, and height to get the answer

3 0
3 years ago
Find the quadratic function y = ax2 + bx+c whose graph passes through the given points.
mash [69]
The function is y=emc^2+y=mca
4 0
2 years ago
Briony invests some money. Interest is paid on the money at a rate of 2% per annum for the first year and 1% per annum for the s
nalin [4]

Answer:

Brionny invested £8400.

Step-by-step explanation:

Simple Interest

This is a simple interest problem.

The simple interest formula is given by:

E = P*I*t

In which E is the amount of interest earned, P is the principal(the initial amount of money), I is the interest rate(yearly, as a decimal) and t is the time.

After t years, the total amount of money is:

T = E + P

In this question:

We divide in two intervals, the first year and the second year. We have to know that the amount after the end of the first year is the principal at the start of the second year.

First year:

Amount of 2% interest, during 1 year.

So the interest earned is:

E = P*I*t = P*0.02*1 = 0.02P

The total amount at the end of the first year is:

T = E + P = 0.02P + P = 1.02P

Second year:

We have that:

P = 1.02P

The interest earned is of:

E = P*I*t = 1.02P*0.01*1 = 0.0102P

The total amount is:

T = E + P = 0.0102P + 1.02P = 1.0302P

After two years, the investment is worth £8653.68 How much did Briony invest?

So

1.0302P = 8653.68

P = \frac{8653.68}{1.0302}

P = 8400

Brionny invested £8400.

3 0
3 years ago
According to the American Lung Association, 7% of the population has lung disease. Of those having lung disease, 90% are smokers
postnew [5]

Answer:

Probability that a smoker has lung disease = 0.2132

Step-by-step explanation:

Let L = event that % of population having lung disease, P(L) = 0.07

So,% of population not having lung disease, P(L') = 1 - P(L) = 1 - 0.07 = 0.93

S = event that person is smoker

% of population that are smokers given they are having lung disease, P(S/L) = 0.90

% of population that are smokers given they are not having lung disease, P(S/L') = 0.25

We know that, conditional probability formula is given by;

                        P(S/L) = \frac{P(S\bigcap L)}{P(L)}  

                        P(S\bigcap L) = P(S/L) * P(L)

                                      = 0.90 * 0.07 = 0.063

So,  P(S\bigcap L) = 0.063 .

Now, probability that a smoker has lung disease is given by = P(L/S)

      P(L/S) = \frac{P(S\bigcap L)}{P(S)}

P(S) = P(S/L) * P(L) + P(S/L') * P(L')

       = 0.90 * 0.07 + 0.25 * 0.93 = 0.2955

Therefore, P(L/S) = \frac{0.063}{0.2955} = 0.2132

Hence, probability that a smoker has lung disease is 0.2132 .

7 0
3 years ago
A young boy is growing at a rate of 3.5 cm per month. He is currently 90 cm tall. At that rate, in how many months will the boy
Olenka [21]
It will take months for the boy to grow to a height of 132cm. 132-90= 42 cm left to grow. 42÷3.5= 12months, or a year.
7 0
3 years ago
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