Question

Along a road lies an odd number of stones of weight 10 kg each, placed at intervals of 10 metres. These stones
have to be assembled around the middle stone. Nirvah, a stone loader can carry only one stone of 10 kg at a
time. He started the job with one of the end stones by carrying them in succession. In carrying all the stones,
he covered a distance of 3 km. Find the number of stones.
​

Answer 1

Answer:

300 stones

Step-by-step explanation:

3km=3000m

if each stone is placed after 10m

then

3000÷10=300

therefore,there are 300 stones

Answer 2

Along a road lies an odd number of stones of weight 10 kg each, placed at intervals of 10 metres. These stones  have to be assembled around the middle stone. Nirvah, a stone loader can carry only one stone of 10 kg at a

time. He started the job with one of the end stones by carrying them in succession. In carrying all the stones,

he covered a distance of 3 km. Find the number of stones.

• Given,
• There are odd number of stones placed along a road side.
• Therefore, let the number of stones be = 2n+1
• Nirvah covered a distance of 3 km = 3000 m
• Since the stones are placed 10 meters apart on both left and right sides, we have,
• 3 × 10n + 2[10(n−1)+10(n−2)+..+10]+ 2[10(n−1)+10(n−2)+..+10] = 3000
• 3 × 10n + 4[10(n−1)+10(n−2)+..+10]= 3000
• 30n + 40[(n-1)+(n-2)+......+1]= 3000
• 30n + 40 [(n-1)/2](1+n-1)= 3000
• upon solving, we get,
• 2n^2 + n-300 =0
• (n-12)(2n+25)=0
• ∴n =12
• Hence the total number of stones
• =2n+1
• =2(12)+1
• =25