<em>2400 is increased by 30%.</em>
so,
2400 + (30/100 * 2400)
2400 + (30 * 24)
2400 + 720
3120
<em>this number is decreased by 20%.</em>
so,
3120 - (20/100 * 3120)
3120 - (2 * 312)
3120 - 624
2496
therefore, the final number will be 2496.
6 gallons in 4 1/2 seconds to travel 1/4 mile
Multiply through by 4
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The dragster will :
use 24 gallons in 18 seconds to travel 1 mile.
For a two-tailed test we need to halve 0.01, giving 0.005. Then we need to sutract 0.005 from 0.5, giving 0.5 - 0.005 = 0.495. Looking up the p value of 0.495 in an inverse normal probability table we obtain the value z = 2.5758. Therefore the critical values are -2.5758 and 2.5758.