In some code, letters P, Q, R, S, T represent numbers 4, 5, 10, 12, 15. It is not known which letter…
In some code, letters P, Q, R, S, T represent numbers 4, 5, 10, 12, 15. It is not known which letter represents which number. If Q – S = 2S and T = R + S + 3, then what is the value of P + R – T?
1
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3
Cannot be determined due to insufficient data
Solution
From $Q - S = 2S$, we get $Q = 3S$. The only valid pairs from {4,5,10,12,15} are S = 4, Q = 12 or S = 5, Q = 15. Testing S = 4, Q = 12 with $T = R + S + 3 = R + 7$ forces T = 12 = Q, a contradiction. Testing S = 5, Q = 15 with $T = R + 8$ gives R = 4, T = 12. Then P = 10. So $P + R - T = 10 + 4 - 12 = 2$.