Add 7.3×10^7+1.8×10^7. Which is the correct sum?
A. 9.1×10^14
B. 9.1+10^7
C. 9.1×10^7
D. 8.1×10^7
To add the numbers in scientific notation, the coefficients must be added and the exponents must remain the same.
7.3×10^7 + 1.8×10^7 = (7.3 + 1.8) × 10^7
= 9.1 × 10^7
So, the correct sum is:
C. 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?
A. 3.58×10^6
B. 35.8+10^5
C. 4.75×10^11
D. 4.75×10^5
To find the sum of the populations of the two cities, we simply add the coefficients and keep the exponent the same.
3.45×10^6 + 1.3×10^5 = (3.45 + 0.13) × 10^6
= 3.58 × 10^6
So, the sum of the populations is:
A. 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
A. 2.953×10^5 pounds
B. 29,530 pounds
C. 4.33×105 pounds
D. 15,302.8 pounds
To find the total weight of the dump truck with the added trash, we add the weight of the empty truck to the weight of the trash.
2.8×10^5 + 1.53×10^4 = (2.8 + 0.153) × 10^5
= 2.953 × 10^5
So, the weight of the dump truck with the added trash is:
A. 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.
A. 11,463,000,000
B. 516,300,000,000
C. 447,000,000,000
D. 4.4637×10^11
To find the half-life of uranium-238, we add the given value of the half-life of uranium-235 to the additional time of 4.463×10^11 years.
700,000,000 + 4.463×10^11 = 4.463×10^11 + 7×10^8 = 4.4637×10^11 years
So, the half-life of uranium-238 is:
D. 4.4637×10^11
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.
Responses
A. 385,280,000,000
B. 512×10^9
C. 5.12×10^11
D. 385.28×10^11
To find the total storage of the phone after purchasing the additional bytes, we add the initial storage to the additional bytes.
1.28×10^11 + 3.84×10^11 = (1.28 + 3.84) × 10^11
= 5.12 × 10^11
So, the phone would have:
C. 5.12×10^11 bytes of storage.
To add numbers written in scientific notation, you need to ensure that the exponents are the same.
In this case, 7.3×10^7 and 1.8×10^7 have the same exponent (7), so you can simply add the coefficients (7.3 and 1.8) to find the sum.
7.3 + 1.8 = 9.1
Since the exponents remain the same, the correct sum is 9.1×10^7.
Therefore, the correct answer is C. 9.1×10^7.