Out of 53 teachers 36 drink tea 18 drink coffee, 10 drink neither. how many drink both?
Let T be tea drinkers
Let C be coffee drinkers
Let (T & C) be Tea & Coffee drinkers.
And 53 are total. So we use the Union formula relation:
C U T = C + T - (C & T)
53 = 18 + 36 - (C & T)
C & T = 53 - (Not C & Not T) since we subtract people who don't drink coffee and don't drink tea
C & T = 53 - 10 = 43
C U T = 18 + 36 - 43
C U T = 11
Let T be tea drinkers
Let C be coffee drinkers
Let (T & C) be Tea & Coffee drinkers.
And 53 are total. So we use the Union formula relation:
C U T = C + T - (C & T)
53 = 18 + 36 - (C & T)
C & T = 53 - (Not C & Not T) since we subtract people who don't drink coffee and don't drink tea
C & T = 53 - 10 = 43
C U T = 18 + 36 - 43
C U T = 11