Question

Sathish is going on a 2100-kilometer road trip with 2 friends, whom he will pick up 150 kilometers after he begins the trip and drop off when there are 150 kilometer remaining. The car consumes 6 liters of gas for every 100 kilometers, and gas costs $1.20 per liter.

Sathish will pay for all of the gas when he is alone in the car, but he and his friends will split the cost evenly when they are together.
How much will Sathish pay for gas?

Answer 1

He will pay $ 64.8

Explanation:

Given,

The total distance of the trip = 2100 km,

∵ Sathish pick up his 2 friends 150 kilometers after he begins the trip and drop off when there are 150 kilometer remaining.

So, the number of kilometres for which he and his friends pay the costs = 2100 - (150+150)

= 2100 - 300

= 1800 km,

Now, the quantity of gas for 100 km = 6 liters,

So, the quantity of gas for 1800 km = 18 × 6 = 108 liters,

If the cost of gas is $ 1.20 per liters,

Then the total cost paid by them ( when satish is not alone )

`=\text{gas consumed in liters}* \text{cost per liters}`

`=108* 1.2`

`=\$ 129.6`

∵ they split this cost evenly,

So, the share of satish ( when he is with his friend ) =
`(129.6)/(3)` = $ 43.2

For the remaining 300 km, he paid the cost of gas,

Again, the quantity of gas for 100 km = 6 liters

⇒ The quantity of gas for 300 km = 18 liters,

Thus, the cost he paid when he was alone = 18 × cost of gas for 1 liter

= 18 × 1.2

= $ 21.6

Hence, the total amount paid by satish = $ 43.2 + $ 21.6 = $ 64.8

Answer 2

Satish will pay $64.8

Explanation:

Kilometres when Satish is alone

150 kilometres in the beginning

150 kilometres in the end

Total: 300 kilometres

Kilometres when Satish is with friends

Total km: 2100

Satish Travelled alone: 300

Kilometres when Satish is with friends: 2100-300 = 1800 km

Litres of gas when Satish is alone

6 litres of gas per 100 kilometres

6 x 3 for 300 kilometres = 18 litres

Litres of gas when Satish is with friends

6 litres of gas per 100 kilometres

6 x 18 for 1800 kilometres = 108 litres

Cost of gas when Satish is alone

$1.2 per litre

18 x 1.2 = $21.6

Cost of gas when Satish is with friends

$1.2 per litre

108 x 1.2 = $129.6

Cost for each friend = $129.6/3 = $43.2

Satish will pay: Cost when travelled with friends + Cost when travelled alone

=$43.2+ $21.6

=$64.8

So, Satish will pay $64.8