Maths question from Social Forest Worker exam, 2026 by JKSSB
A survey of 500 people was conducted regarding their ownership of Smartwatches (S), Tablets (T), and VR Headsets (V). 285 people own a Smartwatch, 215 own a Tablet, and 115 own a VR Headset. Exactly 45 people own all three devices. There are 70 who own a Smartwatch and a VR Headset, while 50 own a Tablet and a VR Headset. 50 people own none of these devices. How many people own a Smartwatch and a Tablet, but not a VR Headset?
Last updated Jul 21, 2026
Correct Answer:
Option A —
45
Step-by-Step Breakdown
1. Determine the Group Sizes
Total people surveyed: 500
People owning no devices: 50
People owning at least one device: five hundred minus fifty, which equals 450
2. Break Down the VR Headset Group
Total VR Headset owners: 115
People owning all three devices: 45
People owning a Smartwatch and a VR Headset: 70
Removing the forty-five who own all three leaves 25 people who own a Smartwatch and a VR Headset, but not a Tablet.
People owning a Tablet and a VR Headset: 50
Removing the forty-five who own all three leaves 5 people who own a Tablet and a VR Headset, but not a Smartwatch.
Now subtract these sub-groups from the total VR Headset owners to find those who own only a VR Headset:
One hundred fifteen minus twenty-five minus five minus forty-five leaves 40 people owning only a VR Headset.
3. Find the Total Overlap Between Smartwatch and Tablet
Using the total numbers for each device:
Adding the total for Smartwatches (285), Tablets (215), and VR Headsets (115) gives 615.
Adding the known overlaps for Smartwatch with VR Headset (70) and Tablet with VR Headset (50) gives 120.
Subtracting this combined overlap of one hundred twenty from six hundred fifteen leaves 495.
Adding back the forty-five people who own all three devices gives 540.
Since four hundred fifty people own at least one device, the total number of people who own both a Smartwatch and a Tablet is the difference between five hundred forty and four hundred fifty, which equals 90.
4. Calculate Smartwatch and Tablet (No VR Headset)
Total owning both Smartwatch and Tablet: 90
Subtract the people who also own a VR Headset: 45
Ninety minus forty-five leaves 45 people.
Answer verified by Quintessence Classes faculty — Karan Nagar, Srinagar.
