**New Learning Composite Mathematics SK Gupta Anubhuti Gangal Class 7 Data Handling Self Practice 15A Solution**

**(1)** Her mean score

= (80+85+90+71+60+100)/6

= 81

**(2)** His mean score =

(138+144+155+142+167+172)/6

= 153

**(3)**

(a) 1^{st} 5 natural no – 1, 2, 3, 4, 5

Mean = (1+2+3+4+5)/5

= 15/5

=3

(b) 1^{st} 7 whole no – 0, 1, 2, 3, 4, 5, 6

Mean = (0+1+2+3+4+5+6)/7

= 21/7

= 3

Or, 312 + X = 80x 5

Or, 312 + X = 400

Or, X = 400 – 312

Or, X = 88

Ans: – She should secure 88 marks in her next test.

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