The Owner of a Hobby Store Bought a Case of 9-Volt

question 26

Short Answer

The owner of a hobby store bought a case of 9-volt batteries for $70.00. He marked the price up such that his profit was $2.80 per battery. After selling 20 batteries, the store owner had recovered his cost. How many 9-volt batteries are in a case?

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Definitions:

Sliding Filament Mechanism

The process by which muscles contract, involving the sliding of actin and myosin filaments past each other.

Crossbridge

A structure formed when myosin heads in muscle fibers attach to actin filaments during muscle contraction.

Sarcoplasm

The cytoplasm of a muscle cell, containing organelles, including the mitochondria and sarcoplasmic reticulum.

Electromyograph

A diagnostic tool used to measure the electrical activity of muscles during contraction and at rest.