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Estimate the total number of light bulbs currently used in Delhi

Updated: Nov 18, 2022

Mobiprep has created step by step solution to estimation questions for all product management and consulting interview questions to help you with the mastering placement interviews. So letâ€™s get started with the estimation questions.

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In this estimation question we have analysed the market size of total number of light bulbs currently used in Delhi. Check out the step-by-step answer created by Mobiprep experts.

Estimation Question Step-1: Segmentation

Lets say, we need to estimate only the LED Lamps.

Estimation Question Step-2: Initiation

Now for street lamp, we need to estimate the road network and then assume that say 90% is well lit by lamps. Next we assume a lamp at every 10 meters apart and each street lamp post has two bulbs.

Homes can be estimated by family members. Lets look at this one in larger details.

Number of People in Delhi = 150 Lac people

Avg. number of people per house= 4 to 5

Therefore, 30 lacs to 37.5 lacs , say 35 lac families.

2 LED for Bathroom

2 LED for kitchen

3 LED for bedroom

5 LED for drawing room

Therefore, for 1 BHK = 5 + 3 + 2 + 2 = 12 Lamps

For 2 BHK = 5 + 2 +(2 + 3) + (2 + 3) + 2 = 19 Lamps ~ 20 Lamps

For 3 BHK = 19 + 5 = 24 Lamps ~ 25 Lamps

For 4 BHK = 24 + 5 = 29 Lamps ~ 30 Lamps

Therefore, an apartment say has 40 lamps

Now also, a below poverty line and low income people will refrain from buying an LED (due to its high price)

Also average lamps for 1BHK & 2 BHK be 15 Lamps,

Therefore,

= (0.1 * 15 * 3.15 Lac) + (0.5 * 15 * 14Lac) + (7.7 * 25 + 7.7 * 30 Lac) + (7 * 40Lac)

= 4.725 Lac + 105 Lac + 231Lac + 192.5 Lac + 280 Lac

= 811.225 Lacs

or 8.11 Crores Lamps (For household purposes)

Estimation Question Step-3: Solution

Avg. market revenue for the current year :

-> First time buyer + Repeat Order

Let the economy of Delhi grow by 8% and Let the lamps industry grow by say 10% due to various Govt. Schemes and push for LED Lamps.

(We know that the industry for incandescent lamp and CFL is Shrinking)

First Time buyers = 8.11 * 0.1 Crore

= 0.81 Crores (80 Lacs approx.) -----(a)

Repeat Buyers = 8.11 Crores /Avg. life of the LED

Let Avg. life of LED be 2.5 yrs

= (8.11 * 4 )/ 10 Crores (as 10/4=2.5)

= 3.244 Crores -----(b)

Total = (a) + (b)

= 3.244 Crore + 0.8 Crore

= 4.044 Crore LED Lamps

Further question can be to estimate the revenue of the Industry. Note so for, we have calculated for houses (residential purposes). To estimate the lamps used throughout Delhi, a more rigorous approach is needed.

Therefore,

= 4 Crore * ( 0.3 * 120 + 0.5 * 160 + 0.2 * 200 )

= 4 Crore * ( 36 + 80 + 40 )

= 4 Crore * 156

= 624 Crores

Note again , this is the estimate of residential use only.