A car accelerates at a constant rate from zero to 32.6 m/s in 10 seconds and then slows to 14.8 m/s in 5 seconds. What is its average acceleration to the nearest tenth of a m/s2 during the 15 seconds?

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What was the acceleration during the first 10 seconds in the previous problem?

This question was answered when it was reposted later by "perry".