एक हेयर स्टाइलिस्ट ने पहली बार एक नया हेयरकट 50 मिनट में किया। यदि स्टाइलिस्ट को दूसरा हेयरकट पूरा करने में 35 मिनट लगे, तो लर्निंग दर (learning rate) क्या है?

A 75% learning curve has been determined to be appropriate for a particular task. For a learning rate of 75%, the value of the index of learning b is -0.4150375. The initial timing of the person performing that job was 50 minutes. If the task needs to be performed 500 times, how many minutes of work will be required (to the nearest minute)?