The average height of 50 pupils in a class is 150 cm. Five of them whose height is 146 cm, leave the class and five others whose average height is 156 cm, join. The new average height of the pupils of the class (in cm) is __________ .

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The average height of 50 pupils in a class is 150 cm. Five of them whose height is 146 cm, leave the class and five others whose average height is 156 cm, join. The new average height of the pupils of the class (in cm) is __________ .

A. 149
B. 151
C. 152
D. 153
Total height = 150 * 50 = 7500 cm.
New average = [7500 – 5 * 146 + 5 * 156 ] / 50 = 151 cm