70 percent of the employees in a multinational corporation have VCD players, 75 percent have microwave ovens, 80 percent have ACs and 85 percent have washing machines. At least what percentage of employees has all four gadgets?
[CAT 2003 Re-Test]

(1) 15%(2) 5%(3) 10%
(4) Cannot be determined

Solution:
70% have VCD Players.
30% do not have VCD Players.

75% have microwave ovens.
25% do not have microwave ovens.

80% have ACs.
20% do not have ACs.

85% have washing machines.
15% do not have washing machines.

30 + 25 + 15 + 20 = 90% of employees do not have at least 1 gadget.

Minimum percentage of employees who has all the four gadgets
= 100 − 90 = 10%
Hence, option 3.

Alternatively,
Minimum percentage of employees which possess both VCDs and Microwaves
= 70% + 75% − 100%
= 45%

Minimum percentage of employees which possess both ACs and Washing machines
= 80% + 85% − 100%
= 65%
Minimum percentage of employees which possess all the four gadgets
= 45% + 65% − 100%
= 10%