Question

enrichment: fossil fuels
the table below shows the amount of fossil fuels produced in the united states fro 2017. the numbers represent quadrillions of btus, or british thermal units, which measuring energy.
calculate the total amount of fossil fuels produced in each year and enter the val table. then answer the questions on a separate sheet of paper.
fossil fuel production
u.s. fossil fuel production (in quadrillions of btus)

year	coal	oil	natural gas	total produced
1967	13.8	18.7	17.9
1977	15.8	17.5	19.6
1987	20.1	17.7	17.1
1997	23.2	13.6	19.5
2007	23.5	10.8	19.8
2017*	15	19	27

Explanation:

Step1: Calculate total for 1957

Add coal, oil, natural gas: $13.1 + 15.2 + 10.6$
$13.1 + 15.2 = 28.3$; $28.3 + 10.6 = 38.9$

Step2: Calculate total for 1967

Add coal, oil, natural gas: $13.8 + 18.7 + 17.9$
$13.8 + 18.7 = 32.5$; $32.5 + 17.9 = 50.4$

Step3: Calculate total for 1977

Add coal, oil, natural gas: $15.8 + 17.5 + 19.6$
$15.8 + 17.5 = 33.3$; $33.3 + 19.6 = 52.9$

Step4: Calculate total for 1987

Add coal, oil, natural gas: $20.1 + 17.7 + 17.1$
$20.1 + 17.7 = 37.8$; $37.8 + 17.1 = 54.9$

Step5: Calculate total for 1997

Add coal, oil, natural gas: $23.2 + 13.6 + 19.5$
$23.2 + 13.6 = 36.8$; $36.8 + 19.5 = 56.3$

Step6: Calculate total for 2007

Add coal, oil, natural gas: $23.5 + 10.8 + 19.8$
$23.5 + 10.8 = 34.3$; $34.3 + 19.8 = 54.1$

Step7: Calculate total for 2017

Add coal, oil, natural gas: $15 + 19 + 27$
$15 + 19 = 34$; $34 + 27 = 61$

Answer:

1957: 38.9
1967: 50.4
1977: 52.9
1987: 54.9
1997: 56.3
2007: 54.1
2017: 61