Choose the student who correctly used guess and check to solve the unknown number the difference of a number and four and twelve

ivan's work
(4)(3)=12 the answer is 3

sara's work
48÷4=12 the answer is 48

hannah's work
16-4=12 the answer is 16

betty's work 12-4=8 the answer is 8​

Acompany manufactures three types of cabinets. it makes 110 cabinets each week. in the first week, the sum of the number of type-1 cabinets and twice the number of type-2 cabinets produced was 10 more than the number of type-3 cabinets produced. the next week, the number of type-1 cabinets produced was three times more than in the first week, no type-2 cabinets were produced, and the number of type-3 cabinets produced was the same as in the previous week.