Which of the following is a correct estimation of 49 x 3?

To arrive at a correct estimation of 49 multiplied by 3, it is useful to consider rounding the numbers to facilitate easier calculations. Rounding 49 to the nearest ten gives us 50. When you multiply 50 by 3, the result is 150. This result indicates that the actual product will be close to this value, but since 49 is slightly less than 50, the actual product should be a bit less than 150.

Therefore, examining the choices provided, 140 serves as a reasonable estimation. It accounts for the slight decrement from the rounded figure while remaining close to the expected product. Recognizing that 49 is just under 50 influences the estimated answer, guiding one to approximate downward. The other figures are notably further away from this estimation, demonstrating their unreliability in this context.