Add 7.3×10^7+1.8×10^7 . Which is the correct sum?(1 point)
Responses
9.1×101^4
9.1×10^7
8.1×10^7
9.1+10^7
The correct sum of 7.3×10^7 + 1.8×10^7 is 9.1×10^7.
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
3.58×10^6
3.58 times 10 superscript 6 baseline
4.75×101^1
4.75 times 10 superscript 11 baseline
35.8+10^5
35.8 plus 10 superscript 5 baseline
4.75×10^5
The sum of the populations of the two cities in scientific notation is 3.58×10^6.
An empty dump truck weighs about 2.8×10^5 pounds. How much does it weigh if 15,300 pounds of trash is added? The answer should be in scientific notation.(1 point)
Responses
29,530 pounds
2.953×10^5 pounds
4.33×10^5 pounds
15,302.8 pounds
The weight of the dump truck with 15,300 pounds of trash added can be represented in scientific notation as 2.953×10^5 pounds.
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
4.4637×10^11
4.4637 times 10 superscript 11 baseline
447,000,000,000
447,000,000,000
516,300,000,000
516,300,000,000
11,463,000,000
11,463,000,000
The half-life of uranium-238 is 4.463 × 10^11 years.
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)
385.28×10^11
385,280,000,000
512×10^9
5.12×10^11
If you buy the additional 384,000,000,000 bytes, the phone would have a total storage of 5.12×10^11 bytes.
To add numbers written in scientific notation, you add the coefficients and keep the same base raised to the power of the exponent.
In this case, to add 7.3×10^7 and 1.8×10^7, you would add the coefficients 7.3 and 1.8 which gives you 9.1. Then, you keep the base 10 and add the exponents 7 and 7 which gives you 14. Therefore, the sum is 9.1×10^14.
So, the correct sum is 9.1×10^14.
Among the given options, 9.1×10^7 is the correct answer.