The weight of an ant averages about 3×10−6 kg. There are about 1×1016 ants in the world. What is the approximate weight in kilograms of all the ants in the world? Write the answer in scientific notation.

that answer was wrong

The average human heart beats about 3.5×107 times per year. The current population of Massachusetts is about 7×106 people. About how many heartbeats occur in Massachusetts per year? Write the answer in scientific notation. Express the answer to the exact decimal place.

that answer is wrong

Apologies for the mistake. Let's recalculate the number of heartbeats in Massachusetts per year:

The average number of heartbeats per year for one person is 3.5×10^7.
The current population of Massachusetts is 7×10^6.

To find the total number of heartbeats, we multiply the average number of heartbeats per year by the population:

Number of heartbeats = (3.5×10^7 heartbeats/person/year) * (7×10^6 people)

Using the laws of exponents, we can simplify this expression:

Number of heartbeats = 3.5×7×10^7×10^6 = 24.5×10^7×10^6 = 24.5×10^13

Therefore, approximately 24.5×10^13 heartbeats occur in Massachusetts per year.

3.5x10^7+7x10^6

The sun generates about 4×10^26 joules of energy every second. There are about 3.15×10^7 seconds in a year. About how many joules of energy does the sun generate in a year? Write the answer in scientific notation. Express the answer to the exact decimal place

To find out how many joules of energy the sun generates in a year, we need to multiply the amount of energy generated per second (4×10^26 joules) by the number of seconds in a year (3.15×10^7).

(4×10^26 joules/second) * (3.15×10^7 seconds) = 4×3.15×10^26×10^7 = 12.6×10^33 joules

To express this in scientific notation with the exact decimal place, we can rewrite it as:

1.26×10^34 joules

Therefore, the sun generates approximately 1.26×10^34 joules of energy in a year.

The average newborn weighs 7.5 pounds. About 4.1×10^6 babies are born in the United States every year. What is the approximate total weight in pounds of all the babies born in the U.S. in a year? Write the answer in scientific notation, expressed to the exact decimal place.

To find the approximate total weight in pounds of all the babies born in the U.S. in a year, we need to multiply the average weight of a newborn (7.5 pounds) by the number of babies born in the U.S. every year (4.1×10^6).

(7.5 pounds/baby) * (4.1×10^6 babies) = 7.5×4.1×10^6 pounds

To simplify this expression, we multiply 7.5 by 4.1:

7.5 * 4.1 = 30.75

Therefore, the approximate total weight in pounds of all the babies born in the U.S. in a year is 30.75×10^6 pounds.

To express this in scientific notation with the exact decimal place, we can rewrite it as:

3.075×10^7 pounds

Therefore, the approximate total weight in pounds of all the babies born in the U.S. in a year is 3.075×10^7 pounds.

In a given year, about 1.52×10^10 pieces of first-class mail are delivered in the U.S. If each piece of mail carries a stamp costing $0.55, what is the total cost in dollars to deliver all the pieces? Write the answer in scientific notation, expressed to the exact decimal place.