Official papers

Official 2022 Paper 2 · Q16

Paper 2Logic & proof

In this question, a1,…,a100a_1,\ldots,a_{100} and b1,…,b100b_1,\ldots,b_{100} and c1,…,c100c_1,\ldots,c_{100} are three sequences of integers such that

an≤bn+cna_n\le b_n+c_n

for each nn.

Which of the following statements must be true?

  • I. (minimum of a1,…,a100)≤(minimum of b1,…,b100)+(minimum of c1,…,c100)\begin{aligned}(\text{minimum of }a_1,\ldots,a_{100})\le{}&(\text{minimum of }b_1,\ldots,b_{100})\\&+(\text{minimum of }c_1,\ldots,c_{100})\end{aligned}
  • II. (minimum of a1,…,a100)≥(minimum of b1,…,b100)+(minimum of c1,…,c100)\begin{aligned}(\text{minimum of }a_1,\ldots,a_{100})\ge{}&(\text{minimum of }b_1,\ldots,b_{100})\\&+(\text{minimum of }c_1,\ldots,c_{100})\end{aligned}
  • III. (maximum of a1,…,a100)≤(maximum of b1,…,b100)+(maximum of c1,…,c100)\begin{aligned}(\text{maximum of }a_1,\ldots,a_{100})\le{}&(\text{maximum of }b_1,\ldots,b_{100})\\&+(\text{maximum of }c_1,\ldots,c_{100})\end{aligned}
Anone of them
BI only
CII only
DIII only
EI and II only
FI and III only
GII and III only
HI, II and III

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