Which two digits and signs need to be interchanged so as to balance t...
According to the BODMAS rule
Option 1 : 4 and 3; + and -
Given:
442 - 13 + 12 × 4 ÷ 75 = 79
After interchange the signs;
332 + 14 - 12 × 3 ÷ 75 = 79
By BODMAS rule
332 + 14 - 12 × 0.04 = 79
332 + 14 – 0.48 = 79
346 – 0.48 = 79
345.52 = 79 (LHS ≠ RHS)
Option 2 : 1 and 2; ÷ and ×
Given:
442 - 13 + 12 × 4 ÷ 75 = 79
After interchange the signs;
441 - 23 + 21 ÷ 4 × 75 = 79
By BODMAS rule
441 - 23 + 5.25 × 75 = 79
441 - 23 + 393.75 = 79
834.75 – 23 = 79
811.75 ≠ 79 (LHS ≠ RHS)
Option 3 : 7 and 3; - and ÷
Given:
442 - 13 + 12 × 4 ÷ 75 = 79
After interchange the signs;
442 ÷ 17 + 12 × 4 - 35 = 39
By BODMAS rule
26 + 12 × 4 - 35 = 39
26 + 48 - 35 = 39
74 - 35 = 39
39 = 39 (LHS = RHS)
Option 4 : 7 and 2; × and +
Given:
447 - 13 + 17 × 4 ÷ 25 = 29
After interchange the signs;
442 - 13 × 12 + 4 ÷ 75 = 79
By BODMAS rule
442 - 13 × 12 + 0.054 = 79
442 - 156 + 0.054 = 79
442.054 - 156 = 79
286.054 ≠ 79 (LHS ≠ RHS)
Hence, the answer is “7 and 3; - and ÷”.