In a School of 140 pupils,every pupil takes at least one of the languages French,German and Spanish.90 pupils take French,70 take German,75 take Spanish,35 take french and German,30 take French and Spanish and 40 take German and Spanish.
70 take Spanish and french or german which would suggest 5 but we know that the number taking german and french or Spanish is higher than the overall number taking german so that 5 must be taking all three languages