Answer: 60000 households have both cable television and videocassette recorders.
Explanation:
Let x represent the number of households that have both cable television and videocassette recorders.
In the city, 80 percent of the households have cable television.
If there are 150,000 households in the city, then the number of households that have cable television would be
80/100 × 150000 = 120000
Also, 60 percent of the households have videocassette recorders. It means that the number of households that have videocassette recorders would be
60/100 × 150000 = 90000
The number that have only only cable television is 120000 - x
The number that have only only videocassette recorders is
90000 - x
Therefore,
120000 - x + 90000 - x + x = 150000
210000 - x = 150000
x = 210000 - 150000
x = 60000