How did the temperature change if: At first it increased by 25% and then decreased by 40%

24.6 % decrease

Step-by-step explanation:

Let x be the original temperature

Increase by 25%

x + .25x

1.25x

Decrease by 40%

The amount decreased is

(1.25x) *.40

.496x

Subtract that from 1.25x

1.25x - .496x

.754x

We need to find the percent decrease

1 - .754 = .246

24.6 % decrease

Temperature decreased by 25%

Step-by-step explanation:

Let initial temperature be t

Step 1

Increase by 25%:

Step 2

Decrease by 40%:

Temperature changed from t to 0.75 t

The difference in %:

Temperature decreased by 25%

i think the answer is b.

step-by-step explanation:

not 100% sure though.

hello,

b) 62.47% of the students are between 14 and 18 years old.

step-by-step explanation:

mean = 15 and standard deviation = 2

student between 14 to 18

formula used z-score

for age 14 , z score

using z-table , p(z> -0.5)=0.3085

for age 18 , z score

using z-table , p(z< 1.5)=0.9332

p(-0.5< z< 1.5)=0.9332-0.3085 = 0.6247

thus, 62.47% of the students are between 14 and 18 years old.

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