Add 7.3×10^7+1.8×10^7. Which is the correct sum?(1 point)

Responses

9.1×10^14
9.1 times 10 superscript 14 baseline

8.1×10^7
8.1 times 10 superscript 7 baseline

9.1+10^7
9.1 plus 10 superscript 7 baseline

9.1×10^7

9.1 times 10 superscript 7 baseline

The population of a city is given as 3.45×10^6. A nearby city has a population of 1.3×10^5. What is the sum of the populations of the two cities in scientific notation?(1 point)

Responses

35.8+105
35.8 plus 10 superscript 5 baseline

4.75×1011
4.75 times 10 superscript 11 baseline

3.58×106
3.58 times 10 superscript 6 baseline

4.75×10^5

3.58×10^6

An empty dump truck weighs about 2.8×105 pounds. How much does it weigh if 15,300 pounds of trash is added? The answer should be in scientific notation.(1 point)

Responses

4.33×105 pounds
4.33 times 10 superscript 5 baseline pounds

15,302.8 pounds
15,302.8 pounds

29,530 pounds
29,530 pounds

2.953×10^5 pounds

2.953×10^5 pounds

Question

The half-life of uranium-235 is 700,000,000 years. The half-life of uranium-238 is 4.463×10^11 years longer. What is the half-life of uranium-238? The answer should be in decimal form.(1 point)
Responses

4.4637×1011
4.4637 times 10 superscript 11 baseline

516,300,000,000
516,300,000,000

447,000,000,000
447,000,000,000

11,463,000,000

447,000,000,000

A mobile phone holds 1.28×10^11 bytes of storage. You can also pay more money to get an additional 384,000,000,000 bytes. How much storage would your phone have if you buy the additional bytes? The answer should be in scientific notation.(1 point)

Responses

385.28×1011
385.28 times 10 superscript 11 baseline

5.12×1011
5.12 times 10 superscript 11 baseline

385,280,000,000
385,280,000,000

512×10^9

385.28×10^11

To add 7.3×10^7 and 1.8×10^7, you need to add the numerical parts and keep the exponential part the same.

Here's how to do it:

1. Add the numerical parts: 7.3 + 1.8 = 9.1.
2. Keep the exponential part the same: Since both numbers have the same exponential part (10^7), you can just keep it as 10^7.

Putting it together, the correct sum is 9.1×10^7.